Mutant lactic bacteria with a capacity for overexpressing at least one peptidase

ABSTRACT

A mutant lactic bacteria with a capacity for overexpressing one or more peptidases, wherein gene codY is inactivated.

RELATED APPLICATION

[0001] This is a continuation of International Application No. PCT/FR0002869, with an international filing date of Oct. 13, 2000, which is based on French Patent Application No. 99/12924, filed Oct. 15, 1999.

FIELD OF THE INVENTION

[0002] This invention concerns mutants of lactic bacteria, such as Lactococcus lactis, with a capacity for overexpressing at least one and preferably multiple peptidases. These mutants exhibit strong peptidolytic activities which enable acceleration of the degradation of casein in amino acids. These mutants are thus most particularly useful for augmenting the maturation rate of cheeses since the amino acids are precursors in the synthesis of aromas. The invention also concerns a method for identifying these mutants and genetic constructions for implementing this method. Finally, the invention also concerns the use of these mutant bacteria in a cheese fabrication and/or maturation process.

BACKGROUND

[0003]Lactococcus lactis has a complex proteolytic system for degrading milk proteins, especially casein. Casein is the dominant protein in milk and provides the amino acids required for growth [12]. Casein is degraded into oligopeptides by a wall protease. These oligopeptides enter the cell via specific transport systems and then are hydrolyzed into amino acids inside the cell by peptidases [14]. In addition to their role in the nitrogenous nutrition of L. lactis, the peptidases can also have an important role in the development of flavors during the maturation of certain cheeses.

[0004] Ten peptidase genes have been cloned and their products characterized biochemically in L. lactis. They are grouped into different classes according to the position and nature of the peptide bond that they hydrolyze and often have a broad specificity [14]. Few studies are available at present on the regulation of the expression of these peptidases in L. lactis and solely the regulation of the wall protease has been studied in an in-depth manner [18, 19].

SUMMARY OF THE INVENTION

[0005] This invention relates to a mutant lactic bacteria with a capacity for overexpressing one or more peptidases, wherein gene codY is inactivated.

[0006] This invention also relates to a recombinant vector for identifying or selecting mutant lactic bacteria with a capacity for overexpressing one or more peptidases, wherein gene code Y is inactivated, including a marker gene fused to a peptidase gene or a promoter of the gene, a replication origin inactivated after integration in the bacteria, an antibiotic marker and at least a part of gene cluA.

[0007] This invention further relates to a method for identifying or selecting a mutant lactic bacterium with a capacity for overexpressing one or more peptidases, wherein gene code Y is inactivated, including transferring a peptidase gene or a promoter of the gene into a bacterium by conjugation with a vector including a marker gene fused to a peptidase gene or a promoter of the gene, a replication origin inactivated after integration in the bacteria, an antibiotic marker and at least a part of gene cluA, culturing the bacteria in the presence of peptides, and measuring activity of the reporter gene.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Other advantages and characteristics of the invention will become manifest from the examples below. These examples concern the production by mutagenesis of mutants of L. lactis according to the invention, and with reference to the attached figures in which:

[0009]FIG. 1 shows luciferase activity of different transcriptional fusions at optical density (OD) 0.4 in amino acid (AA) chemically defined medium (CDM) and casitone (Cas) chemically defined medium.

[0010]FIG. 2 shows the repression of the transcription in A of the regulated promoters and in B of the unregulated promoters. These results were obtained from the extraction of the total mRNAs of the wild strain cultured in CDM+amino acids (AA) and CDM+casitone (Cas) at different optical densities (0.2, 0.6, 0.8, 1.2). The hybridizations were performed with different specific probes of the peptidase promoters. The regulated promoters correspond to a decrease in the RNA under growth conditions in the presence of casitone, which is the reflection of a repression of the transcription.

[0011]FIG. 3 is a schematic representation of the different factors intervening in the expression of the peptidases of L. lactis and which enabled conception of the different mutants of the invention.

[0012]FIG. 4 shows an alignment of the sequences of the codY genes of L. lactis and of Bacillus subtilis.

DETAILED DESCRIPTION

[0013] Expression of certain genes in Lactococcus lactis can be critical in cheese fabrication processes. Thus, we took into consideration that evaluating the level of expression of these genes can be performed by determining the efficacy of their promoters since transcription is one of the parameters that control the expression of genes. We, therefore, developed tools based on the use of reporter genes. They constructed vectors suitable for the systematic study of numerous promoters in different cellular and environmental contexts and which can be easily transferred into a large number of strains of L. lactis. These vectors were used to study the variability of expression of the enzymes of the proteolytic system of L. lactis. The expression of sixteen genes coding for the enzymes implicated in the proteolysis of the strain L. lactis subsp. cremoris MG1363 as well as two genes of the wall protease of strains WG2 and SK11 could be characterized either by means of the vectors we developed or by detecting messenger RNAs using the Northern blot technique [8].

[0014] The studies carried out in the framework of the present invention on the characterization of the expression of the genes coding for the peptidases, proteases and transport proteins of L. lactis enabled demonstration of a coordinated regulation of their expression and, thus, determination of the factors that can affect this expression. We accordingly performed a systematic study of the transcription of the sixteen genes referred to above as implicated in proteolysis.

[0015] We thereby showed that the transcription of eight of these sixteen tested genes is regulated and repressed simultaneously by dipeptides via the intracellular pool of branched amino acids: isoleucine, leucine and valine. It is a question of the promoters of the genes of the following peptidases:

[0016] prtP, which is the wall protease [14] and, more particularly, prtPWG, which is a wall protease isolated from strain WG2, and prtPSK11, which is a wall protease isolated from strain SK11;

[0017] pepN and pep C, which are the aminopeptidases of major general specificity in the cell [14];

[0018] pepO, which is an endopeptidase implicated in the degradation of oligopeptides [14];

[0019] opp, which is the operon coding for the oligopeptide entry system [14];

[0020] dtpt, which codes for a transport protein of the hydrophilic dipeptides and tripeptides [14];

[0021] pepDA2, which codes for a general dipeptidase.

[0022] We also showed that the transcription of the genes of the proteolytic system in L. lactis is regulated by the products of diverse genes. We can cite, most particularly, the gene codY which constitutes a central regulator repressing transcription of the genes of the proteolytic system in L. lactis. We can also mention one of the genes of the operon lev and a gene coding for a β-glucosidase.

[0023] We, therefore, implemented a random mutagenesis strategy applied to the strain MG1363 [21] to find the regulators of the transcription of these peptidases. The fusion of the second promoter of the operon opp-pepO (PpepOA) to the gene of the β-galactosidase was used as a reporter to visualize the mutants whose transcription of this promoter is deregulated. We thereby isolated mutants of L. lactis obtained by insertion of a transposon.

[0024] Thus, an advantage of the invention is mutants of lactic bacteria with a capacity for overexpressing one or more peptidases, characterized in that at least one of the negative regulation factors of at least one of the peptidase genes of said bacteria is inactivated.

[0025] This inactivation can be total or partial. The term “total inactivation” is understood to mean that the factor is not expressed at all, whereas the term “partial inactivation” is understood to mean that said factor is still expressed but not sufficiently for observing the negative regulation effect found in a nonmutated bacterium.

[0026] The invention concerns most particularly mutants of lactic bacteria with a capacity for overexpressing one or more peptidases, characterized in that at least one of the negative regulation factors of at least one of the peptidase genes of the bacteria is inactivated, the negative regulation factor being selected from among the group comprising the gene codY, the genes of the operon lev, a gene coding a protein homologous with a β-glucosidase.

[0027] A first form of implementation of such an inactivation consists of a modification of the DNA sequence of one of the genes or a sequence implicated in the expression or regulation of the gene. A second form of implementation of such an inactivation consists of a modification of a gene coding for a cofactor protein required for the activity of one of the genes and/or the modification of a gene implicated in the expression or regulation of this cofactor protein.

[0028] As mutant lactic bacteria according to the invention, the mutants of L. lactis and S. Thermophilus are preferred.

[0029] The term “mutants of lactic bacteria” according to the invention is understood more specifically to refer to bacteria that have been genetically modified in a manner such that at least one of the negative regulation factors of at least one of the genes of the peptidases is totally or partially inactivated. Inactivation is understood to mean the modification of one or more genes coding for proteins constituting one or more negative regulation factors of the genes of the peptidases such as, for example, codY or the modification of one or more genes coding for the proteins required by the negative regulation factors of the peptidase genes, such as for example the transport elements of the branched amino acids or a protein required for the activity of CODY. The mutants of lactic bacteria according to the invention are advantageously obtained by mutagenesis.

[0030] The invention pertains, more particularly, to mutants of lactic bacteria with a capacity for overexpressing one or more peptidases, characterized in that at least one of the negative regulation factors common to multiple genes of the peptidases is inactivated.

[0031] The invention concerns, more particularly, mutants of lactic bacteria and especially of Lactococcus lactis at least one of whose negative transcription regulation factors common to at least two and preferably three of the promoters of the peptidase genes is inactivated.

[0032] The promoters of the peptidase genes at least one of whose negative transcription regulation factors is inactivated are, for example, selected from among the genes prtP, pepN, pepC, pepX, pepO, pepDA2, dtpT and the operon opp.

[0033] Reference will be made below to the attached sequence listing in which:

[0034] SEQ ID No. 1 represents the sequence of the gene codY of L. lactis MG 1363.

[0035] SEQ ID No. 2 represents the sequence of the gene dtpt of L. lactis MG1363.

[0036] SEQ ID No. 3 represents the sequence of the gene secA of L. lactis IL1403.

[0037] SEQ ID No. 4 represents the sequence of the gene secY of L. lactis IL403.

[0038] SEQ ID No. 5 represents the sequence of the operon lev of L. lactis IL403.

[0039] SEQ ID No. 6 represents a sequence fragment of a gene of L. lactis MG1363 whose product is homologous to a β-glucosidase.

[0040] SEQ ID No. 7 represents the sequence of the gene of L. lactis MG1363 whose product is homologous to a formate dehydrogenase.

[0041] SEQ ID No. 8 represents a part of the sequence of the gene codY of S. thermophilus.

[0042] SEQ ID No. 9 represents the complete sequence of the gene codY of S. thermophilus.

[0043] A first negative regulation factor of the peptidases of lactic bacteria, notably of L. lactis, we identified is constituted by the intracellular pool of branched amino acids which repress transcription of multiple peptidase genes. A first type of mutant is, thus, characterized by modifying this intracellular pool of branched amino acids. “Modification” is preferably understood to entail a decrease in the amount of branched amino acids. An example of modification of the pool of branched amino acids consists of selectively modifying their entry into the cell, notably by blocking one or more of the transport systems:

[0044] of the amino acids,

[0045] of the dipeptides and tripeptides,

[0046] of the oligopeptides.

[0047] The mutants of L. lactis of which at least one of the transport systems of branched amino acids, dipeptides, tripeptides or oligopeptides is blocked are mutants in which at least one of the genes coding for an element of these transport systems is inactivated.

[0048] Mutants of a dipeptide and tripeptide transport system were obtained by random mutagenesis in the gene dtpT [10] of L. lactis whose sequence is given in the attached sequence listing under SEQ ID No. 2. The studies in the prior art on this gene never revealed that there could be mutants of Lactococcus lactis with a capacity for overexpressing one or more peptidases. An example of gene dtpT modified in a mutant is characterized by inserting, for example, the plasmid pGhost-IIS1 after the nucleotides in positions 280 and 470 in sequence SEQ ID No. 2.

[0049] Repression of the transcription of the genes coding for the peptidases is raised in the mutants of the invention and, as previously stated, can result from the variation of the intracellular pool of branched amino acids. Variation of the intracellular pool of branched amino acids can also stem from variation of the degradation of the peptides (dipeptides, tripeptides or oligopeptides). Consequently, the mutants of lactic bacteria and, more particularly, of L. lactis are mutants in which at least one of the genes coding the peptidases responsible for the degradation of these dipeptides, tripeptides or oligopeptides is inactivated.

[0050] An important negative regulation factor we identified is the product of the gene codY which represses the transcription of multiple peptidases at the level of their promoter. In fact, we obtained by mutagenesis mutants of L. lactis inactivated in a gene which is homologous with the gene codY of Bacillus subtilis. In a mutant codY we reconstructed by directed mutagenesis, it was seen that transcription of the gene pepOA and transcription of at least three peptidase genes are not repressed by the dipeptides. Thus, inactivation of the gene codY in L. lactis enables augmentation of the expression of the genes of multiple peptidases by a factor of about 4 to about 55 in a medium containing a source of peptides that normally represses them in the wild strain.

[0051] The DNA sequence of the gene codY of L. lactis and the sequence of the protein codY for which it codes are represented in attached SEQ ID No. 1.

[0052] We also demonstrated the presence of the gene codY in S. thermophilus which, like L. lactis, is a lactic bacterium. The partial DNA sequence of the gene codY of S. thermophilus and the protein sequence for which it codes are represented in attached SEQ ID No. 8. The complete DNA sequence of the gene codY of S. thermophilus and the protein sequence for which it codes are represented in attached SEQ ID No. 9. Thus, the complete or partial inactivation of the gene codY in other lactic bacteria (Streptococcus, Lactobacillus, Pediococcus, Leuconostoc) can also enable augmentation of the expression of peptidases.

[0053] Consequently, a preferred type of lactic bacteria mutants according to the invention, more particularly of L. lactis, is characterized by inactivating the gene codY. A first example of such an inactivation consists in a modification of the DNA sequence of the gene codY, more particularly of the attached sequences SEQ ID No. 1, 8 or 9, or of a sequence implicated in the expression or regulation of this gene. A second example of such an inactivation consists of a modification of a gene coding for a cofactor protein required for the activity of the gene codY and/or the modification of a gene implicated in the expression or regulation of this cofactor protein.

[0054] As previously stated, in the bacteria that are mutant for codY of the invention the expression of at least three peptidases is augmented from about 4 to about 55 times in a medium containing a source of peptides which normally repress their expression. A bacterium mutant for codY according to the invention interrupts the cascade of regulation which leads to repression of the peptidases via the pool of peptides of the external medium. A change of the DNA sequence in the gene codY or in its regulation sequence consists, for example, of a mutation or a deletion which can be implemented by well known mutagenesis methods. Thus, we recorded 13 mutants of codY with, for example, insertion of the plasmid p Ghost-IIS1 after the nucleotides in positions 87, 112, 122, 289, 313, 409, 575, 604, 641, 693, 821, 877 and 882 in the sequence SEQ ID No. 1.

[0055] As previously stated, we characterized other mutants of lactic bacteria, notably of L. lactis, with a capacity for overexpressing one or more peptidases. These are mutants in which at least one of the negative transcription regulation factors of one or more genes of said peptidases is inactivated. The following can be cited as examples of such mutants:

[0056] The mutants in which a gene coding for the proteins implicated in the secretion of the transport proteins of dipeptides or tripeptides is inactivated. It is a question more particularly of mutants in which at least one of the genes secA [3] or secY [13] is modified. The proteins coded by these genes can intervene in the translocation of the protein DtpT which is implicated in the transport of the dipeptides and tripeptides. The sequences of the genes secA and secY of L. lactis are given in the attached sequence listing under numbers SEQ ID No. 3 and SEQ ID No. 4, respectively. Mutants for secA were prepared by insertion of the plasmid pGhost-IIS1 after the nucleotides in positions 1689 and 1698 in sequence SEQ ID No. 3. Mutants for secY were prepared by insertion of the plasmid pGhost-IIS1 after the nucleotides in positions 1273 and 1281 in sequence SEQ ID No. 4.

[0057] The mutants in which one of the genes of the operon lev is inactivated [17]. The genes of the operon lev code for a transport system of sugars. The sequence of the operon lev of L. lactis is given in the attached sequence listing under SEQ ID No. 5. Mutants for the operon lev according to the invention were prepared by insertion of the plasmid pGhost-IIS1 after the nucleotides in positions 40, 108, 1075, 1140, 1145 and 2735 in sequence SEQ ID No. 5.

[0058] The mutants in which at least one of the genes having homology with a gene coding a protein whose structure is of the type of that of a β-glucosidase and/or a formate dehydrogenase is inactivated. The sequence of a gene coding this protein homologous with a β-glucosidase is given in the attached sequence listing under number SEQ ID No. 6. The sequence of a gene coding a formate dehydrogenase is given in the attached sequence listing under number SEQ ID No. 7.

[0059] As above, the term an “inactivated gene” is understood to mean a gene whose sequence or a sequence implicated in its expression or its regulation is modified.

[0060] Consequently, another preferred type of mutant of lactic bacteria according to the invention, more particularly of L. lactis, is characterized by the inactivation of one of the genes of the operon lev. A first example of such an inactivation consists of a modification of the DNA sequence of one of the genes of the operon lev, more particularly, of the attached SEQ ID No. 5, or a sequence implicated in its expression or the regulation of one of the genes of this operon. A second example of such an inactivation consists of a modification of a gene coding for a cofactor protein required for the activity of one of the genes of the operon lev and/or the modification of a gene implicated in the expression or regulation of this cofactor protein.

[0061] A third preferred type of mutant of lactic bacteria according to the invention, more particularly, of L. lactis is characterized by the inactivation of a gene coding for a protein homologous with a β-glucosidase. A first example of such an inactivation consists of modification of the DNA sequence of a gene coding for a β-glucosidase, more particularly, of attached SEQ ID No. 6, or of a sequence implicated in the expression or regulation of this gene. A second example of such an inactivation consists of a modification of a gene coding for a cofactor protein required for the activity of a gene coding for a β-glucosidase and/or the modification of a gene implicated in the expression or regulation of this cofactor protein.

[0062] It is understood that the mutants according to the invention can also be characterized by more than one of the mutations described above.

[0063] As previously stated, we developed tools based on the use of reporter genes such as the luciferase gene of Vibrio harveyi. The expression of luciferase, which is detected by an emission of light, makes it easy to measure the activity of promoters, even in complex media [4]. The vectors pVar we constructed contain a replication origin inactivated after integration, an antibiotic marker and a part of the gene cluA [6]. This latter fragment allows the plasmid to integrate itself by homologous recombination in the sex factor. This factor is a conjugative element of 60 kb present in integrated form in the chromosome of certain strains of L. lactis. The integrated constructions in the sex factor at the level of the gene cluA in a strain can thus be transferred into numerous strains of L. lactis by conjugation.

[0064] The invention, thus, also concerns a recombinant vector for identifying or selecting mutant bacteria according to the invention. This vector is characterized in that it comprises a marker gene fused to a peptidase gene or a promoter of this gene, a replication origin inactivated after integration in the bacterium, an antibiotic marker and a part of the gene cluA.

[0065] Such a vector makes it possible to distinguish a mutant strain according to the invention from a wild strain incapable of overexpressing one or more peptidases. The following method can be used to distinguish the strains. A vector pVar containing the promoter PpepOA of the operon opp-pepO, fused to the luciferase gene, is transferred into the strains by conjugation to determine the level of expression of peptidases in the strains. Measurements of the luciferase activity under the control of PpepOA indicate whether the transcription of at least the gene pepO is derepressed in these strains. Constructions with other promoters enable verification of the number of peptidase genes whose transcription is derepressed. The reference luciferase activities of the wild strain which reflect the repression of the transcription of the peptidase genes during growth in the presence of peptides, via the pool of branched amino acids, are listed in FIG. 1.

[0066] Consequently, the invention also concerns a method for the identification or selection of a mutant lactic bacterium according to the invention, characterized in that a peptidase gene or a promoter of this gene is transferred into a bacterium by conjugation with the vector defined above, that the bacterium is cultured in the presence of peptides and, using any appropriate means, the activity of the reporter gene is measured which reflects the repression of the transcription of the peptidase genes.

[0067] The reporter gene is advantageously the luciferase gene.

[0068] The invention also concerns the use of mutants of lactic bacteria as described above or a mixture of them in a cheese fabrication and/or maturation process. In an advantageous manner, the mutants of lactic bacteria as described above or a mixture of them are used in a fabrication and/or maturation process for soft or pressed cheeses.

[0069] I—Material and Methods

[0070] 1) Bacteria Strains, Media, Vectors and DNA Manipulations

[0071] Strain L. lactis MG1363 was cultured at 30° C. in M17 glucose medium. If necessary, 5 μg/ml of erythromycin was added to the culture medium. The peptidase promoters under study (PepP, PepA, PepF2, PepDA1, PepOA, PepQ, PepX, PepOD, PepM, PepT, PepN and PepC) and the two promoters of the operon opp (pepOA/pepOD) were amplified by PCR by means of specific primers from the chromosome of the strain L. lactis subsp. cremoris MG1363. A series of conditional replication vectors containing luciferase reporter genes of Vibrio harveyi and a fragment of the sex factor (gene cluA) was constructed. pVar-1 was used for fusing to the luciferase genes the DNA fragments obtained by PCR and corresponding to the different promoters.

[0072] 2) Integration of the Transcriptional Fusions on the Chromosome of MG1363 and Conjugation

[0073] After transformation of strain MG1363 by the plasmids pVar-1 containing the peptidase promoters, the fusions were integrated in the chromosome by homologous recombination, either at the peptidase promoter locus or at the locus of the sex factor (in the gene cluA). Identification of the integration locus was performed by means of suitable primers by PCR amplification and hybridization of a Southern gel. Transfer of the sex factor was implemented by conjugation between two strains [5].

[0074] 3) Determination of the Luciferase Activity in L. lactis

[0075] Measurements of the luciferase activity were performed on the Berthold Lumat luminometer LB9501. A milliliter of L. lactis culture was mixed with 5 μl of nonaldehyde and the light emission directly measured. The peak value was brought to OD_(600 nm) of the culture and luciferase activity was measured during the entire growth. The luciferase activity shown in FIG. 1 was measured at OD_(500 nm)=0.4 and expressed in 10³ lux/OD.

[0076] 4) Chemically Defined Medium (CDM)

[0077] This chemically defined medium (CDM) is defined in Sissler et al. [22]. The nitrogen source of this medium is a mixture of amino acids. In the “casitone CDM”, there was added an extract of casitones (milk caseins degraded by pancreatic enzymes) which is a source of small peptides.

[0078] 5) Constructions: PpepOA-βgal.

[0079] The second promoter of the operon opp-pepO (PpepOA) of strain MG1363 was amplified by the following oligonucleotides (GGGAATTCTTTGGGAACAATGATAA and CGGGATCCGTTACTTCTGAACCA) and the amplified 500-pb fragment was cloned in the plasmid pJIM762 at the site EcoRI-BamHI upstream of the β-galactosidase gene of Escherichia coli (E. Guédon, unpublished results). This plasmid, whose β-galactosidase gene is under the control of the expression signals of PpepOA, was integrated into the chromosome of MG1363 by homologous recombination at the promoter locus. The transcription at PpepOA was repressed by the dipeptides contained in the casitone of the medium and the strain containing the fusion was white on a chemically defined medium (CDM) containing casitones. Transcription at PpepOA was derepressed on a CDM containing amino acids as nitrogen source and the strain containing the fusion was blue (the strain was cultured with phospho-β-galactoside (P-β-gal) in both cases).

[0080] 6) Plasmid Pghost8-ISS1

[0081] This conditional replication plasmid (heat-sensitive replication protein) had a tetracycline antibiotic marker and an insertion sequence ISS1 [16]. Augmentation of the temperature from 30° C. to 37° C. inhibited replication of this plasmid and the tetracycline-resistant strains obtained contained the plasmid integrated in the chromosome. It integrated itself in a random manner in the chromosome of L. lactis by replication transposition [16].

[0082] 7) Mutagenesis By Transposition

[0083] Random mutagenesis was performed with the heat-sensitive plasmid pGhost8-ISS1 in strain MG1363 containing the fusion promoter PpepOA-β-gal. In casitone CDM, in the presence of P-β-gal, out of 50,000 white clones isolated, 46 had a phenotype of blue color. Expression of β-gal fusion was derepressed in these mutants. The plasmid pGhost8-ISS1 was, thus, inserted in a gene whose product is a direct or indirect repressor of the expression of PpepOA.

[0084] 8) Identification of the Mutants By Cloning Junctions

[0085] Transposition by ISS1 into the chromosome yields an insertion of pGhost8 surrounded by a duplicate copy of ISS1. The junctions were cloned using unique restriction sites (EcoRI and HindIII) present on pGhost8. Digestion of the chromosome by these enzymes made it possible to obtain the plasmid pGhost8 containing the flanking regions. The transposition site was thereby characterized by sequencing the junctions with the following oligonucleotides (for the junction EcoRI: TCACCTCATATAAATTCCCCA and AAATGGAACGCTCTTCGG) (for the junction HindIII: CGCCAGGGTTTTCCCA GTCACGAC and ACCAACAGCGACAATAATCACA).

[0086] 9) Mutant codY

[0087] Random mutagenesis made it possible to obtain, among others, mutant codY for which the transcription of multiple genes coding for the proteolytic enzymes is deregulated. Inactivation of this gene in L. lactis augments expression of the genes opp-pepO, pepN and pepC by a factor of 55, 14 and 4, respectively, in CDM with casitones in which the expression was normally repressed by the peptide source.

[0088] 10) Inactivation of codY By Simple Crossing-Over

[0089] A 540-pb PCR fragment was amplified by the following oligonucleotides (CAGTATGACTGAACGCTTGGC and GCGATAACATGCCCTTCTTCA) and cloned in the plasmid pJIM2242. This plasmid was integrated into the gene codY by simple crossing-over and a mutant codY was verified by Southern hybridization. This mutant has the same phenotype as the codY mutants obtained by mutagenesis.

[0090] 11) Other Mutants

[0091] Random mutagenesis enabled identification of many other codY mutants. Mutations of the genes dtpT, of the operon lev, secA, secY, and genes coding for a helicase, a β-glucosidase and an enzyme homologous with a formate dehydrogenase also led to mutants overexpressing at least pepO or additional peptidases.

[0092] II—Results

[0093] 1) Construction of the Vector pVar-1

[0094] Integrative vectors making it possible to follow the expression of a reporter gene under the control of a promoter on the chromosome were constructed. The luciferase genes of Vibrio harveyi were used as a reporter gene. The luciferase activity of the transcriptional fusions with the promoters of peptidase genes is the reflection of the expression of the peptidase genes [11, 20]. A vector which replicates itself in a conditional manner was used to integrate the transcriptional fusions on the chromosome [15]. This vector was conceived to be easily transferable by conjugation, in particular, in industrial strains that are difficult to transform. A fragment (gene cluA) of the 60-kb chromosome element called the “sex factor”, which is possessed by certain strains of lactococci, was introduced into this vector. This element is capable of high-frequency self transfer in the species L. lactis [7]. By integrating our transcriptional fusions into this sex factor, these fusions were rendered transferable to other strains of lactococci by conjugation of the sex factor. Among different vectors constructed, the pVar-l contains an erythromycin-resistance gene in addition to the components described above. It was verified that the transcriptional fusions integrated at the promoter locus or in the gene cluA with pVar-1 had identical luciferase activities [9].

[0095] 2) Expression of Fusions with the Promoters of Genes Coding for Peptidases

[0096] The promoters of 11 genes coding for peptidases (pep) of L. lactis MG1363: pepA, pepC, pepDA1, pepF2, pepM, pepN, pepP, pepQ, pepT, pepx; and the two promoters of the operon opp-pepO (PpepOA and PpepOD) in which is found the gene pepO, were cloned, fused to the gene lux in the vector pVar-1 and integrated by homologous recombination into the chromosome of L. lactis MG1363 at the locus of the different promoters. Both protease promoters (prt of strains WG2 and SK11) were fused to the luciferase gene on a plasmid. Expression of these fusions was determined in CDM and casitone CDM, and the values of the luciferase measurements are presented in FIG. 1. In CDM, the fusions were grouped together into different classes on the basis of the measured luciferase levels. The strongest luciferase activity was obtained with the plasmid fusions containing the promoters of the genes prt (10·10³ lux/OD (10³)). For the chromosome fusions, the strongest luciferase activity was obtained with the promoters PpepN, PpepC, PpepOA and PpepOD (1 to 5 10·10³ lux/OD (10³), an average activity was obtained with the promoters of the genes pepQ, pepX, pepM and pepT (200 to 300 lux/OD (10³)) and weak activity was obtained with the promoters of the genes pepP, pepA, pepF2 and pepDA1 (20 to 80 lux/OD (10³)). It should be noted that the highest expression levels were obtained with the fusions containing the promoters of the genes coding for the peptidases of very broad specificity (pepC, pepN, pepO) and for a transport system of oligopeptides (Opp) which is essential for the growth of lactococci in a milk medium. Expression of peptidase genes was diminished in casitone CDM medium which contains a nitrogen source constituted by amino acids and peptides (FIG. 1). The force of the promoters PpepP, PpepA, PpepF2, PpepDA1, PpepQ, PpepT and PpepM was diminished 2 to 3 times in casitone CDM, whereas the force of the promoters PpepX, PpepC, PpepN, PprtPWG2, PprtPSK11, pepO and the operon opp-pepO was repressed 5, 7, 13, 21, 12 and 153 times, respectively, by the dipeptides of the culture medium via the pool of branched amino acids in the cell. Northern Blot analysis of the transcripts confirmed the results obtained with the transcriptional fusions and revealed that the transcription of the genes pepDA2 and dtpT but not that of dtpP was repressed by the peptides of the casitone (FIG. 2).

[0097] 3) Obtaining and Characterizing Derepressed Mutants

[0098] On a peptide-rich medium and in the presence of P-βgal, the wild strain containing the fusion PpepOA-βgal yielded white colonies because expression of the fusion is repressed. The mutants obtained yield blue colonies because expression of the fusion PpepOA-βgal is derepressed.

[0099] Different genes of the mutants in which pGhost was inserted were identified (codY, dtpT, the operon lev, secA, secY and the genes coding for a β-glucosidase and an enzyme homologous with a formate dehydrogenase (fdh)). The Northern Blot analysis of the mRNAs of a mutant strain cultured in a peptide-rich medium confirmed that the transcription of the gene pepO was no longer repressed in the mutants of the genes codY, dtpT, fdh and the operon lev. The derepression of pepO in the mutants of the genes coding for secA, SecY and β-glucosidase has yet to be confirmed.

[0100] 4) Characterization of the Expression of Peptidases in the Deregulated Mutants

[0101] Transcription of the peptidase genes was characterized in the mutants by measurement of activity. Two classes of mutants could be obtained: one class for which the transcription of multiple peptidases is derepressed (pleiotropic mutants) and the other class in which only the transcription of the gene pepO is derepressed.

[0102] Mutants of the genes codY, dtpT: in an M17 rich medium containing repressor peptides, the luciferase activities were measured in a wild strain and in a codY mutant for the promoters PpepOD, PpepC and PpepN, and in a dtpT mutant for the promoter PpepOD. In a mutant codY, repression of the transcription diminished by a factor of 35, 4 and 14, respectively for the genes pepOD, pepC and PepN. In a mutant dtpT, repression of the transcription diminished by a factor of 15 for the gene pepOD.

BIBLIOGRAPHIC REFERENCES

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[0110] 8) Guédon E., Renault P., Ehrlich S. D., Delorme C. “Environmental factors involved in the transcriptional regulation of 18 proteolysis components in Lactococci” (submitted for publication).

[0111] 9) E. Guédon, P. Renault, S. D. Ehrlich and C. Delorme. “Evaluation of the diversity of genetic expression in lactococci: development of a tool and its application to peptidases.” (Accepted for publication in “Science des aliments”).

[0112] 10) Hagting A. et al., 1994, “The di- and tri-peptide transport protein of Lactococcus lactis”, J. Biol. Chem., 269, 11391-11399.

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[0115] 13) Koivula T., Palva I., Hemila H., “Nucleotide sequence of the secY gene from Lactococcus lactis and identification of conserved regions by comparison of four secY proteins”, 1991, FEBS Lett. 288:114-8.

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[0117] 15) Law J., Buist G., Haandrikman A., Kok J., Venema G., Leenhouts K., 1995. A system to generate chromosomal mutations in Lactococcus lactis which allows fast analysis of targeted genes. J. Bacteriol., 177, 7011-7018.

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[0119] 17) Martin-Verstraete I., Debarbouille M., Klier A., Rapoport G. “Levanase operon of Bacillus subtilis includes a fructose specific phosphotransferase system regulating the expression of the operon” 1990, J. Mol. Biol., 244, 657-671.

[0120] 18) Marugg J. D., Meijer W., Van Kranenburg R., Laverman P., Bruinenberg P. G., DeVos W. M., 1995. Medium-dependent regulation of proteinase gene expression in Lactococcus lactis, control of transcription initiation by specific dipeptides. J. Bacteriol., 177, 2982-2989.

[0121] 19) Meijer W., Marugg J. D., Hugenholtz J., 1996. Regulation of proteolytic enzyme activity in Lactococcus lactis. Appl. Environ. Microbiol., 62, 156-161.

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[0124] 22) Sissler M., Delorme C., Bond J., Ehrlich S. D., Renault P., Francklyn C., 1999, “An aminoacyl-tRNA synthetase paralog with a catalytic role in histidine biosynthesis” PNAS, 96:8985-8990.

1 29 1 937 DNA Lactococcus lactis CDS (121)..(897) sequence of codY from L. lactis MG1363 1 agagtaattt ttctgacaat tttttattgt ttttccatat gcttttttat gttatactga 60 ttatgaaaaa ttttgtataa aaacaagaat ataaaaaaat aggagaacaa agtggctaca 120 tta ctt gaa aaa aca cgt aaa atc acc gcg att ttg caa gat gga gtg 168 Leu Leu Glu Lys Thr Arg Lys Ile Thr Ala Ile Leu Gln Asp Gly Val 1 5 10 15 acc gat ttg caa caa gag ttg cca tac aac agt atg act gaa cgc ttg 216 Thr Asp Leu Gln Gln Glu Leu Pro Tyr Asn Ser Met Thr Glu Arg Leu 20 25 30 gca aac gtc att gat tgc aac gcc tgc gtg att aat acg aag ggc gag 264 Ala Asn Val Ile Asp Cys Asn Ala Cys Val Ile Asn Thr Lys Gly Glu 35 40 45 ttg ctt ggt tac tca ttg cct tac aat aca aac aat gat cgc gtt gac 312 Leu Leu Gly Tyr Ser Leu Pro Tyr Asn Thr Asn Asn Asp Arg Val Asp 50 55 60 caa ttt ttc tac gat cgt aaa ttg cct gac gaa tac gtt cgt gca gca 360 Gln Phe Phe Tyr Asp Arg Lys Leu Pro Asp Glu Tyr Val Arg Ala Ala 65 70 75 80 gta cgt att tac gat aca atg gca aac gtt cct gtt gat cgt cct tta 408 Val Arg Ile Tyr Asp Thr Met Ala Asn Val Pro Val Asp Arg Pro Leu 85 90 95 gca att ttc cca gaa gaa agt ctt agc gat ttt cca aaa ggt gta aca 456 Ala Ile Phe Pro Glu Glu Ser Leu Ser Asp Phe Pro Lys Gly Val Thr 100 105 110 act tta gcg cct atc tat ggt tct gga atg cgt ctt gga aca ttt att 504 Thr Leu Ala Pro Ile Tyr Gly Ser Gly Met Arg Leu Gly Thr Phe Ile 115 120 125 atg tgg cgt gaa gat ggt gaa ttt aca gat gac gat ctt gtt ttg gtt 552 Met Trp Arg Glu Asp Gly Glu Phe Thr Asp Asp Asp Leu Val Leu Val 130 135 140 gag ctt gca aca aca gta atc ggt gta caa ctc tca aac ctt aaa ctt 600 Glu Leu Ala Thr Thr Val Ile Gly Val Gln Leu Ser Asn Leu Lys Leu 145 150 155 160 gaa caa atg gaa gaa aat atc cgt aaa gac act atg gca aca atg gct 648 Glu Gln Met Glu Glu Asn Ile Arg Lys Asp Thr Met Ala Thr Met Ala 165 170 175 gtt aat aca ctt tct tac tca gaa atg aaa gct gtc aaa gca att att 696 Val Asn Thr Leu Ser Tyr Ser Glu Met Lys Ala Val Lys Ala Ile Ile 180 185 190 gaa gaa ctt gat ggt gaa gaa ggg cat gtt att gcc tct gtc att gct 744 Glu Glu Leu Asp Gly Glu Glu Gly His Val Ile Ala Ser Val Ile Ala 195 200 205 gac aag att ggt att aca cgt tca gtg att gtt aat gct tta cgt aaa 792 Asp Lys Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala Leu Arg Lys 210 215 220 ctt gaa tct gct ggt gtt att gaa tca cgt tca ctt ggt atg aaa gga 840 Leu Glu Ser Ala Gly Val Ile Glu Ser Arg Ser Leu Gly Met Lys Gly 225 230 235 240 act tat ctt aaa gtt ctt aat act ggt ttg ttt gat aaa ctt gct gga 888 Thr Tyr Leu Lys Val Leu Asn Thr Gly Leu Phe Asp Lys Leu Ala Gly 245 250 255 cgt aat ttc taaaagtcag agcttaacgc ttgttctttt atcatttgtt 937 Arg Asn Phe 2 1389 DNA Lactococcus lactis CDS (1)..(1389) sequence of dtpT from L. lactis IL1403 2 atg cgt gcc att ctg gtt tat tac ctc tat gca ttg aca act gca gat 48 Met Arg Ala Ile Leu Val Tyr Tyr Leu Tyr Ala Leu Thr Thr Ala Asp 1 5 10 15 aac gca ggt tta gga ctt cct aaa gct cag gca atg gcg att gta agt 96 Asn Ala Gly Leu Gly Leu Pro Lys Ala Gln Ala Met Ala Ile Val Ser 20 25 30 att tat ggt gca ctt gtc tat ctt tca aca att gtt ggg gga tgg gtt 144 Ile Tyr Gly Ala Leu Val Tyr Leu Ser Thr Ile Val Gly Gly Trp Val 35 40 45 gct gac cgg ttg ttg ggc gct tcg cgc aca atc ttc ttg ggt ggt att 192 Ala Asp Arg Leu Leu Gly Ala Ser Arg Thr Ile Phe Leu Gly Gly Ile 50 55 60 tta atc act tta gga cac gtc gct tta gca aca cca ttt ggt tta tct 240 Leu Ile Thr Leu Gly His Val Ala Leu Ala Thr Pro Phe Gly Leu Ser 65 70 75 80 tca ctc ttc gtg gca tta ttc ttg att atc tta gga aca ggg atg ctt 288 Ser Leu Phe Val Ala Leu Phe Leu Ile Ile Leu Gly Thr Gly Met Leu 85 90 95 aaa ccc aat att tct aac atg gtt ggg cat cta tat tca aaa gat gac 336 Lys Pro Asn Ile Ser Asn Met Val Gly His Leu Tyr Ser Lys Asp Asp 100 105 110 tca cgt cgt gat act gga ttt aat atc ttt gta gtc gga att aat atg 384 Ser Arg Arg Asp Thr Gly Phe Asn Ile Phe Val Val Gly Ile Asn Met 115 120 125 ggt tct ctg att gct cca ttg att gtt ggg aca gtt gga caa ggc gtg 432 Gly Ser Leu Ile Ala Pro Leu Ile Val Gly Thr Val Gly Gln Gly Val 130 135 140 aac tac cac tta ggt ttc tca ctt gcc gca atc gga atg att ttt gca 480 Asn Tyr His Leu Gly Phe Ser Leu Ala Ala Ile Gly Met Ile Phe Ala 145 150 155 160 tta ttt gct tat tgg tat gga cgt ctt cgt cat ttc cca gaa att gga 528 Leu Phe Ala Tyr Trp Tyr Gly Arg Leu Arg His Phe Pro Glu Ile Gly 165 170 175 cgt gaa cca tct aat cca atg gat gca aaa gca aaa cgt aat ttt att 576 Arg Glu Pro Ser Asn Pro Met Asp Ala Lys Ala Lys Arg Asn Phe Ile 180 185 190 att aca tta acg att gtt ctt atc gtt gct tta atc gga ttt ttc tta 624 Ile Thr Leu Thr Ile Val Leu Ile Val Ala Leu Ile Gly Phe Phe Leu 195 200 205 att tat caa gca agt cct gcg aat ttc atc aat aat ttc att aac gtt 672 Ile Tyr Gln Ala Ser Pro Ala Asn Phe Ile Asn Asn Phe Ile Asn Val 210 215 220 tta tca att atc ggt att gtt gtt cca att att tat ttc gta atg atg 720 Leu Ser Ile Ile Gly Ile Val Val Pro Ile Ile Tyr Phe Val Met Met 225 230 235 240 ttt acc tct aaa aag gta gaa tca gac gaa cgt cgt aaa tta acg gct 768 Phe Thr Ser Lys Lys Val Glu Ser Asp Glu Arg Arg Lys Leu Thr Ala 245 250 255 tat att cct ttg ttc ctt tct gct att gtc ttt tgg gca att gaa gaa 816 Tyr Ile Pro Leu Phe Leu Ser Ala Ile Val Phe Trp Ala Ile Glu Glu 260 265 270 caa agt tct acg att att gcg gtt tgg gga gaa tca cgt tct aac tta 864 Gln Ser Ser Thr Ile Ile Ala Val Trp Gly Glu Ser Arg Ser Asn Leu 275 280 285 aat cct act tgg ttt gga ttt act ttc cat att gac cca tct tgg tac 912 Asn Pro Thr Trp Phe Gly Phe Thr Phe His Ile Asp Pro Ser Trp Tyr 290 295 300 caa ttg ttg aac cca ctc ttc atc gtt ctc ttg tca cct atc ttt gta 960 Gln Leu Leu Asn Pro Leu Phe Ile Val Leu Leu Ser Pro Ile Phe Val 305 310 315 320 cga att tgg aac aaa tta gga gat cgt caa cca tca acc atc gtt aaa 1008 Arg Ile Trp Asn Lys Leu Gly Asp Arg Gln Pro Ser Thr Ile Val Lys 325 330 335 ttt ggt ctt gga ctg atg ttg acc gga gct tct tat ttg att atg aca 1056 Phe Gly Leu Gly Leu Met Leu Thr Gly Ala Ser Tyr Leu Ile Met Thr 340 345 350 ctt cct gga ctc ttg aat ggg act tct gga cgt gcg agt gct ctt tgg 1104 Leu Pro Gly Leu Leu Asn Gly Thr Ser Gly Arg Ala Ser Ala Leu Trp 355 360 365 cta gta ttg atg ttt gct gtt caa atg gca ggt gaa tta ctt gtt tca 1152 Leu Val Leu Met Phe Ala Val Gln Met Ala Gly Glu Leu Leu Val Ser 370 375 380 cca gtt ggt tta tca gtt tca aca aaa tta gcg cca gta gca ttc caa 1200 Pro Val Gly Leu Ser Val Ser Thr Lys Leu Ala Pro Val Ala Phe Gln 385 390 395 400 tct caa atg atg gca atg tgg ttc ttg gca gac tca act tca caa gcg 1248 Ser Gln Met Met Ala Met Trp Phe Leu Ala Asp Ser Thr Ser Gln Ala 405 410 415 att aat gcc caa att aca cct atc ttt aaa gca gca aca gaa gtt cac 1296 Ile Asn Ala Gln Ile Thr Pro Ile Phe Lys Ala Ala Thr Glu Val His 420 425 430 ttc ttt gca att aca ggg att atc ggt att atc gtt gga atc atc ctc 1344 Phe Phe Ala Ile Thr Gly Ile Ile Gly Ile Ile Val Gly Ile Ile Leu 435 440 445 ctt att atc aaa aaa cct att ttg aaa tta atg gga gat gtt cgt 1389 Leu Ile Ile Lys Lys Pro Ile Leu Lys Leu Met Gly Asp Val Arg 450 455 460 3 1719 DNA Lactococcus lactis CDS (1)..(1719) sequence of secA from L. lactis IL1403 3 atg gaa aat gtt gcc tta act cac ttt gta gat aat gct tta cgt gcc 48 Met Glu Asn Val Ala Leu Thr His Phe Val Asp Asn Ala Leu Arg Ala 1 5 10 15 aac ttt atc atg ctt cac gac atc gac tat atg gtt gat gaa aac caa 96 Asn Phe Ile Met Leu His Asp Ile Asp Tyr Met Val Asp Glu Asn Gln 20 25 30 gaa gtt ttg att att gac caa ttt act gga cgt acg atg cct gga cgt 144 Glu Val Leu Ile Ile Asp Gln Phe Thr Gly Arg Thr Met Pro Gly Arg 35 40 45 cgc tat tct gat ggt ctt cac caa gca att gaa gct aaa gaa gct gtg 192 Arg Tyr Ser Asp Gly Leu His Gln Ala Ile Glu Ala Lys Glu Ala Val 50 55 60 cca att caa gat gaa tca aaa aca atg gct tca att acg att caa aac 240 Pro Ile Gln Asp Glu Ser Lys Thr Met Ala Ser Ile Thr Ile Gln Asn 65 70 75 80 tac ttc cgg atg tat aaa aaa ctg tca ggg atg aca ggg act gct aaa 288 Tyr Phe Arg Met Tyr Lys Lys Leu Ser Gly Met Thr Gly Thr Ala Lys 85 90 95 acc gaa gaa gaa gaa ttc cgt gag att tat aac att caa atc aca cca 336 Thr Glu Glu Glu Glu Phe Arg Glu Ile Tyr Asn Ile Gln Ile Thr Pro 100 105 110 att cca acc aac cgt cct gtt caa cgt tta gat cat cca gat tta ctt 384 Ile Pro Thr Asn Arg Pro Val Gln Arg Leu Asp His Pro Asp Leu Leu 115 120 125 tac cca act ttg gaa gct aaa ttt aaa gca gtt att gat gat att aaa 432 Tyr Pro Thr Leu Glu Ala Lys Phe Lys Ala Val Ile Asp Asp Ile Lys 130 135 140 cgt cgt cat gct gaa ggt caa cca ata ttg att ggt act gtt gct gtc 480 Arg Arg His Ala Glu Gly Gln Pro Ile Leu Ile Gly Thr Val Ala Val 145 150 155 160 gaa act tcc gaa ttg att tct aag aaa ttg gtt gaa gca aaa att cct 528 Glu Thr Ser Glu Leu Ile Ser Lys Lys Leu Val Glu Ala Lys Ile Pro 165 170 175 cac gaa gtt ttg aat gcg aaa aat cac ttc cgt gaa gca caa atc atc 576 His Glu Val Leu Asn Ala Lys Asn His Phe Arg Glu Ala Gln Ile Ile 180 185 190 atg aat gcg ggt caa caa gga gca gta acg att gcg acc aac atg gcc 624 Met Asn Ala Gly Gln Gln Gly Ala Val Thr Ile Ala Thr Asn Met Ala 195 200 205 ggt cgt ggg act gat atc aag ctt ggg cct ggt gta att gat cat gta 672 Gly Arg Gly Thr Asp Ile Lys Leu Gly Pro Gly Val Ile Asp His Val 210 215 220 gac cct gaa ttc cga ggt ctt gct gtt att ggt act gag cgt cat gaa 720 Asp Pro Glu Phe Arg Gly Leu Ala Val Ile Gly Thr Glu Arg His Glu 225 230 235 240 tct cgt cgt att gat aat caa tta cgt ggt cgt tct gga cgt caa ggt 768 Ser Arg Arg Ile Asp Asn Gln Leu Arg Gly Arg Ser Gly Arg Gln Gly 245 250 255 gac cca ggg gtt tca caa ttc tat ctt tct ctt gaa gat gaa tta atg 816 Asp Pro Gly Val Ser Gln Phe Tyr Leu Ser Leu Glu Asp Glu Leu Met 260 265 270 aaa cgt ttt ggt tcg gaa cgt gtt tca gct ttc cta gat aga atg cgt 864 Lys Arg Phe Gly Ser Glu Arg Val Ser Ala Phe Leu Asp Arg Met Arg 275 280 285 att tct ggt gaa gat gct gtc atc aaa tct ggc ttg att act cgt cag 912 Ile Ser Gly Glu Asp Ala Val Ile Lys Ser Gly Leu Ile Thr Arg Gln 290 295 300 att gaa agt tca caa aaa cgt gtc gaa gga aat aac tac gat tct cgt 960 Ile Glu Ser Ser Gln Lys Arg Val Glu Gly Asn Asn Tyr Asp Ser Arg 305 310 315 320 aaa caa gtc ttg caa tat gat gat gtc atc cgt gag caa cgt gaa gtt 1008 Lys Gln Val Leu Gln Tyr Asp Asp Val Ile Arg Glu Gln Arg Glu Val 325 330 335 att tat gcg caa cgt cag gaa gtt atc ttg gct aca gaa gat atg act 1056 Ile Tyr Ala Gln Arg Gln Glu Val Ile Leu Ala Thr Glu Asp Met Thr 340 345 350 cct gtt ttg atg ggc atg ttc aag cga aca att gat cgt caa gtg gat 1104 Pro Val Leu Met Gly Met Phe Lys Arg Thr Ile Asp Arg Gln Val Asp 355 360 365 ggt cat gaa ctt gca gga agt ctt aaa gat gaa gaa aat gtc aaa aat 1152 Gly His Glu Leu Ala Gly Ser Leu Lys Asp Glu Glu Asn Val Lys Asn 370 375 380 ctc ttg caa aca tta cac aat aca atg ttg cca gaa gat ggc att gaa 1200 Leu Leu Gln Thr Leu His Asn Thr Met Leu Pro Glu Asp Gly Ile Glu 385 390 395 400 ttg tct gaa ctg aca ggt ttg tca gta caa gca atg aaa gat ttg att 1248 Leu Ser Glu Leu Thr Gly Leu Ser Val Gln Ala Met Lys Asp Leu Ile 405 410 415 ttt gat aaa gtc aaa gct cgt tat gct tca caa atg gaa aaa tta tct 1296 Phe Asp Lys Val Lys Ala Arg Tyr Ala Ser Gln Met Glu Lys Leu Ser 420 425 430 gac cca gaa cgt cag ttg gaa ttc caa cgt gca gtt atc tta cga gtt 1344 Asp Pro Glu Arg Gln Leu Glu Phe Gln Arg Ala Val Ile Leu Arg Val 435 440 445 gtt gat aat aac tgg tca gaa cac att gat gcg ctt gac caa atg cgt 1392 Val Asp Asn Asn Trp Ser Glu His Ile Asp Ala Leu Asp Gln Met Arg 450 455 460 caa tca gta gga ctt cgt ggt tat gcc caa aat aac cct att gtt gaa 1440 Gln Ser Val Gly Leu Arg Gly Tyr Ala Gln Asn Asn Pro Ile Val Glu 465 470 475 480 tat caa gaa gaa tca tat aaa atg tac aat aat atg att ggt gcg att 1488 Tyr Gln Glu Glu Ser Tyr Lys Met Tyr Asn Asn Met Ile Gly Ala Ile 485 490 495 gaa ttt gaa gtg act cgt ttg atg atg aaa gct caa att caa cca caa 1536 Glu Phe Glu Val Thr Arg Leu Met Met Lys Ala Gln Ile Gln Pro Gln 500 505 510 acg gca atc cgt cag gaa gcg cca aga atg aca acc aca gct tca caa 1584 Thr Ala Ile Arg Gln Glu Ala Pro Arg Met Thr Thr Thr Ala Ser Gln 515 520 525 gaa aat att aca aat gtt gat act gaa cat tct gtc agt gaa gaa att 1632 Glu Asn Ile Thr Asn Val Asp Thr Glu His Ser Val Ser Glu Glu Ile 530 535 540 tca ttt gaa aat gtt ggt cgt aac gac ctt tgt cct tgt ggt tct ggt 1680 Ser Phe Glu Asn Val Gly Arg Asn Asp Leu Cys Pro Cys Gly Ser Gly 545 550 555 560 aag aag ttt aaa aat tgt cac gga cgt aca cat att gcc 1719 Lys Lys Phe Lys Asn Cys His Gly Arg Thr His Ile Ala 565 570 4 1317 DNA Lactococcus lactis CDS (1)..(1317) sequence of secY from L. lactis IL1403 4 atg ttt ttt aag acg ctt aag gaa gcc ttt aag gtc aaa gac gtc cga 48 Met Phe Phe Lys Thr Leu Lys Glu Ala Phe Lys Val Lys Asp Val Arg 1 5 10 15 gca aga att ctc ttt acg att ttc atc ctt ttt gtt ttc cgc tta ggt 96 Ala Arg Ile Leu Phe Thr Ile Phe Ile Leu Phe Val Phe Arg Leu Gly 20 25 30 gct cat att acg gta cct ggc gtc aac gtt caa aac tta aca gaa gta 144 Ala His Ile Thr Val Pro Gly Val Asn Val Gln Asn Leu Thr Glu Val 35 40 45 agt aat ctt cct ttc ttg aac atg atg aac ttg gtt tct ggt aat gcc 192 Ser Asn Leu Pro Phe Leu Asn Met Met Asn Leu Val Ser Gly Asn Ala 50 55 60 atg caa aac tac tca ctc ttt gca atg gga gtt tcg cct tat atc act 240 Met Gln Asn Tyr Ser Leu Phe Ala Met Gly Val Ser Pro Tyr Ile Thr 65 70 75 80 gct tca atc att gtt caa ttg ttg caa atg gat att tta cca aaa ttt 288 Ala Ser Ile Ile Val Gln Leu Leu Gln Met Asp Ile Leu Pro Lys Phe 85 90 95 gtt gag tgg tca aaa caa ggg gaa att gga cgt cgt aaa ctg aat caa 336 Val Glu Trp Ser Lys Gln Gly Glu Ile Gly Arg Arg Lys Leu Asn Gln 100 105 110 gcg aca cgt tac att acc tta gtg ctt gct atg gca caa tct atc ggg 384 Ala Thr Arg Tyr Ile Thr Leu Val Leu Ala Met Ala Gln Ser Ile Gly 115 120 125 att act gct ggt ttc caa gcc atg agc tcg tta aat att gtg caa aat 432 Ile Thr Ala Gly Phe Gln Ala Met Ser Ser Leu Asn Ile Val Gln Asn 130 135 140 cca aat tgg caa agc tat ttg atg att ggt gca att ttg acc act ggt 480 Pro Asn Trp Gln Ser Tyr Leu Met Ile Gly Ala Ile Leu Thr Thr Gly 145 150 155 160 tca atg gtt gtc act tgg atg ggt gaa caa att aat gac caa ggt ttt 528 Ser Met Val Val Thr Trp Met Gly Glu Gln Ile Asn Asp Gln Gly Phe 165 170 175 ggc tca ggt gtt tca gta atc atc ttt gct ggg att gtc tct agt att 576 Gly Ser Gly Val Ser Val Ile Ile Phe Ala Gly Ile Val Ser Ser Ile 180 185 190 cca tca gcc atc aaa tct gtt tat gat gaa aaa ttc tta aac gta aga 624 Pro Ser Ala Ile Lys Ser Val Tyr Asp Glu Lys Phe Leu Asn Val Arg 195 200 205 cca tct gaa att cct atg tct tgg ata ttt gtt att gga ttg att ttg 672 Pro Ser Glu Ile Pro Met Ser Trp Ile Phe Val Ile Gly Leu Ile Leu 210 215 220 tca gca att gtc att att tat gtt aca aca ttt gtt caa caa gcg gaa 720 Ser Ala Ile Val Ile Ile Tyr Val Thr Thr Phe Val Gln Gln Ala Glu 225 230 235 240 cgt aaa gta cca att caa tac act aag ttg act caa ggc gca cca aca 768 Arg Lys Val Pro Ile Gln Tyr Thr Lys Leu Thr Gln Gly Ala Pro Thr 245 250 255 agt tcg tac ttt cca ctt cgt gtc aat cca gct ggt gtt atc cca gtt 816 Ser Ser Tyr Phe Pro Leu Arg Val Asn Pro Ala Gly Val Ile Pro Val 260 265 270 atc ttt gct ggt tca att aca act gct cct gct acg atc ttg caa ttc 864 Ile Phe Ala Gly Ser Ile Thr Thr Ala Pro Ala Thr Ile Leu Gln Phe 275 280 285 ttg caa cgt tca caa ggt agc aat gta ggt tgg tta tca acc tta caa 912 Leu Gln Arg Ser Gln Gly Ser Asn Val Gly Trp Leu Ser Thr Leu Gln 290 295 300 aac gcc ttg tca tat acg act tgg aca gga atg ctc ttc tac gca tta 960 Asn Ala Leu Ser Tyr Thr Thr Trp Thr Gly Met Leu Phe Tyr Ala Leu 305 310 315 320 ttg att gtt ctc ttt act ttc ttc tac tca ttc gtt cag gtc aat cct 1008 Leu Ile Val Leu Phe Thr Phe Phe Tyr Ser Phe Val Gln Val Asn Pro 325 330 335 gaa aag atg gct gaa aac ctt caa aaa caa ggc tct tac att cca tct 1056 Glu Lys Met Ala Glu Asn Leu Gln Lys Gln Gly Ser Tyr Ile Pro Ser 340 345 350 gtt cgt ccg ggt aaa gga acc gaa aag tat gtt tct cgt ctc tta atg 1104 Val Arg Pro Gly Lys Gly Thr Glu Lys Tyr Val Ser Arg Leu Leu Met 355 360 365 cgt ctt gca acg gtt ggt tcg ctc ttc ctt gga ttg att tca atc att 1152 Arg Leu Ala Thr Val Gly Ser Leu Phe Leu Gly Leu Ile Ser Ile Ile 370 375 380 cca att gcg gcc caa aac gtt tgg gga ctt cca aaa atc gtc gct ctt 1200 Pro Ile Ala Ala Gln Asn Val Trp Gly Leu Pro Lys Ile Val Ala Leu 385 390 395 400 gga ggg aca tca tta tta atc ttg att caa gtt gcg att caa gca gtt 1248 Gly Gly Thr Ser Leu Leu Ile Leu Ile Gln Val Ala Ile Gln Ala Val 405 410 415 aaa caa ctt gaa gga tat tta ctt aaa cgt aaa tat gca gga ttt atg 1296 Lys Gln Leu Glu Gly Tyr Leu Leu Lys Arg Lys Tyr Ala Gly Phe Met 420 425 430 gat aat cca ctt gaa aca aaa 1317 Asp Asn Pro Leu Glu Thr Lys 435 5 2916 DNA Lactococcus lactis CDS (127)..(1083) CDS (1165)..(1974) CDS (1996)..(2916) misc_feature (1)..(2916) sequence of the lev operon from L. lactis 1403 5 gtaatatttt tatgaaaaca tttgcaaata tcgatttgaa gtagtataat aactaagtaa 60 taatttttat tataatctta tataggaggt tactcacatt gagtatcgga attgttattg 120 cgagcc atg gtg aat tcg ccg cag atc aaa caa tct ggt tct atg att 168 Met Val Asn Ser Pro Gln Ile Lys Gln Ser Gly Ser Met Ile 1 5 10 ttc gga gag caa gaa aaa gta caa gtt gtt act ttt atg cct agc gaa 216 Phe Gly Glu Gln Glu Lys Val Gln Val Val Thr Phe Met Pro Ser Glu 15 20 25 30 gga cca act gat ttg cat gct aaa atc gaa gct gcc atc gca aca ttt 264 Gly Pro Thr Asp Leu His Ala Lys Ile Glu Ala Ala Ile Ala Thr Phe 35 40 45 gat gct gaa gat gaa gta ctt gtc ctt gct gac tta tgg agc ggt tct 312 Asp Ala Glu Asp Glu Val Leu Val Leu Ala Asp Leu Trp Ser Gly Ser 50 55 60 cca ttt aat caa gca agt gca gtg atg ggt gaa aat cca gag cgc aag 360 Pro Phe Asn Gln Ala Ser Ala Val Met Gly Glu Asn Pro Glu Arg Lys 65 70 75 att gct atc atc aca ggc ctc aac ctg cct atg ctt atc caa gcc tac 408 Ile Ala Ile Ile Thr Gly Leu Asn Leu Pro Met Leu Ile Gln Ala Tyr 80 85 90 aca gaa cgc atg atg gat gcg tct gcc ggg gtg gat aaa gtc gta gca 456 Thr Glu Arg Met Met Asp Ala Ser Ala Gly Val Asp Lys Val Val Ala 95 100 105 110 aat att atg aaa gaa gcc aaa ggc ggt att aaa gta cta cct gaa gaa 504 Asn Ile Met Lys Glu Ala Lys Gly Gly Ile Lys Val Leu Pro Glu Glu 115 120 125 ctt caa cct gct gaa gaa act gct gtt gca gct gct ccg gct gct gtt 552 Leu Gln Pro Ala Glu Glu Thr Ala Val Ala Ala Ala Pro Ala Ala Val 130 135 140 caa ggt gcg att cct gaa gga aca gtc atc ggt gat ggt aaa att aaa 600 Gln Gly Ala Ile Pro Glu Gly Thr Val Ile Gly Asp Gly Lys Ile Lys 145 150 155 att aac ctc gct cgt att gac tca cgt ttg ctt cac gga caa gtt gca 648 Ile Asn Leu Ala Arg Ile Asp Ser Arg Leu Leu His Gly Gln Val Ala 160 165 170 act gct tgg act cca gac tca aga gca aac cgc atc atc gtt gtt tct 696 Thr Ala Trp Thr Pro Asp Ser Arg Ala Asn Arg Ile Ile Val Val Ser 175 180 185 190 gac acc gtt tct aaa gat gaa ctt cgt aag aag ctc att gaa caa gcg 744 Asp Thr Val Ser Lys Asp Glu Leu Arg Lys Lys Leu Ile Glu Gln Ala 195 200 205 gct cca act ggt gta aaa gct aac gtt ata cca att aag aaa atg att 792 Ala Pro Thr Gly Val Lys Ala Asn Val Ile Pro Ile Lys Lys Met Ile 210 215 220 gaa gtt gct aaa gac cca cgt ttt ggt gac act aaa gcc ctt ctt ctt 840 Glu Val Ala Lys Asp Pro Arg Phe Gly Asp Thr Lys Ala Leu Leu Leu 225 230 235 ttc gaa acg cca caa gac gct ctt gca aca atc gaa ggt ggc gta cca 888 Phe Glu Thr Pro Gln Asp Ala Leu Ala Thr Ile Glu Gly Gly Val Pro 240 245 250 att gaa aca ttg aac gtt ggt tct atg gct cac tca act ggt aaa aca 936 Ile Glu Thr Leu Asn Val Gly Ser Met Ala His Ser Thr Gly Lys Thr 255 260 265 270 atg ctc aac aaa gtt ctt tct atg gac aaa gat gac gtt gct act ttt 984 Met Leu Asn Lys Val Leu Ser Met Asp Lys Asp Asp Val Ala Thr Phe 275 280 285 gaa aaa ttg cgt gac ctc gga gtt aaa ttc gac gta cgt aaa gtt cca 1032 Glu Lys Leu Arg Asp Leu Gly Val Lys Phe Asp Val Arg Lys Val Pro 290 295 300 gct gac tct aaa tct gac ctc ttt ggt ttg att aac aaa gct gac gta 1080 Ala Asp Ser Lys Ser Asp Leu Phe Gly Leu Ile Asn Lys Ala Asp Val 305 310 315 caa taatcagaat atgctcgtat gatattctga ttactaaaat tgaatattag 1133 Gln gcagccaaat aattaaggag atataaaaaa c atg gaa tac ggt gtt tta tct 1185 Met Glu Tyr Gly Val Leu Ser 320 325 gta atc ttg gtc att gtt gtt gcc ttc ctt gct ggt ctt gaa ggt atc 1233 Val Ile Leu Val Ile Val Val Ala Phe Leu Ala Gly Leu Glu Gly Ile 330 335 340 ctt gac caa tgg caa ttc cac caa cca att atc gcg tgc tcg ctc atc 1281 Leu Asp Gln Trp Gln Phe His Gln Pro Ile Ile Ala Cys Ser Leu Ile 345 350 355 ggt att gtt acc ggt cat gct tct gca ggg att atc ctc ggt ggt tca 1329 Gly Ile Val Thr Gly His Ala Ser Ala Gly Ile Ile Leu Gly Gly Ser 360 365 370 ctt caa ttg atc gct ctt ggt tgg gct aac gtt ggt gcc gct gtc gca 1377 Leu Gln Leu Ile Ala Leu Gly Trp Ala Asn Val Gly Ala Ala Val Ala 375 380 385 390 ccc gat gct gcc ctt gcc tct atc gca tca tct atc ttg atg gtt caa 1425 Pro Asp Ala Ala Leu Ala Ser Ile Ala Ser Ser Ile Leu Met Val Gln 395 400 405 tca aat aac ttt gac ttg act cac atc atg ggt act atc gtt cct gct 1473 Ser Asn Asn Phe Asp Leu Thr His Ile Met Gly Thr Ile Val Pro Ala 410 415 420 gct atc ttg ctt gca act gct ggt ctt gta ttg act act ctt gta cgt 1521 Ala Ile Leu Leu Ala Thr Ala Gly Leu Val Leu Thr Thr Leu Val Arg 425 430 435 atg ctt tca gtt gtg ctc gtt cac caa gct gac cgt gct gct gaa aat 1569 Met Leu Ser Val Val Leu Val His Gln Ala Asp Arg Ala Ala Glu Asn 440 445 450 ggt tca tac tca ggt gtt gaa atg tgg cac ttc atc gcg ctt atc tgt 1617 Gly Ser Tyr Ser Gly Val Glu Met Trp His Phe Ile Ala Leu Ile Cys 455 460 465 470 caa ggt ttg cgt att gct atc cct gct gga ctt ctt ttg gtt atc tca 1665 Gln Gly Leu Arg Ile Ala Ile Pro Ala Gly Leu Leu Leu Val Ile Ser 475 480 485 cca gat gct atc caa aaa gca ctt gct gct att cct cca gtt atc tct 1713 Pro Asp Ala Ile Gln Lys Ala Leu Ala Ala Ile Pro Pro Val Ile Ser 490 495 500 ggc ggt ctt gct gtc ggt ggt ggg atg gtt gtt gcc gtt ggt tat gca 1761 Gly Gly Leu Ala Val Gly Gly Gly Met Val Val Ala Val Gly Tyr Ala 505 510 515 atg gtt atc aac ctt atg gct act cgt gaa gta tgg cca ttc ttc ttc 1809 Met Val Ile Asn Leu Met Ala Thr Arg Glu Val Trp Pro Phe Phe Phe 520 525 530 ctt ggt ttc gct ctc gca cca atc tct gaa tta aca ttg att gca act 1857 Leu Gly Phe Ala Leu Ala Pro Ile Ser Glu Leu Thr Leu Ile Ala Thr 535 540 545 550 ggt gtc ctc ggt gtt gtt atc gct atc gtt tac ctt aac ctc caa gct 1905 Gly Val Leu Gly Val Val Ile Ala Ile Val Tyr Leu Asn Leu Gln Ala 555 560 565 tct ggt ggt tct gga aat ggt act gca tct tca tca ggt gac cca att 1953 Ser Gly Gly Ser Gly Asn Gly Thr Ala Ser Ser Ser Gly Asp Pro Ile 570 575 580 ggc gac atc ttg aac gac tac taagaaagga ggatctaaaa a atg tct gaa 2004 Gly Asp Ile Leu Asn Asp Tyr Met Ser Glu 585 590 aat aaa gta act ctt gat aag aaa atc cgt cgt agc gtt atg tgg cgt 2052 Asn Lys Val Thr Leu Asp Lys Lys Ile Arg Arg Ser Val Met Trp Arg 595 600 605 tca atg ttc ctc caa ggt tct tgg aac tac gaa cgt atg caa aat ggt 2100 Ser Met Phe Leu Gln Gly Ser Trp Asn Tyr Glu Arg Met Gln Asn Gly 610 615 620 ggt tgg gct tac tcg ctc att cca gca ttg aaa aaa ctc tac cct tct 2148 Gly Trp Ala Tyr Ser Leu Ile Pro Ala Leu Lys Lys Leu Tyr Pro Ser 625 630 635 640 ggc gaa gaa gct aaa gaa gct ttg aaa cgt cac ttg gaa ttc ttt aat 2196 Gly Glu Glu Ala Lys Glu Ala Leu Lys Arg His Leu Glu Phe Phe Asn 645 650 655 act cac cca tac gtt gcc gct cct atc atc ggt gta act ctt gcc ctt 2244 Thr His Pro Tyr Val Ala Ala Pro Ile Ile Gly Val Thr Leu Ala Leu 660 665 670 gaa gaa gaa cgt gct aac ggt gct gat atc gat gat gcc gct att caa 2292 Glu Glu Glu Arg Ala Asn Gly Ala Asp Ile Asp Asp Ala Ala Ile Gln 675 680 685 ggg gtt aaa gtt ggt atg atg ggt cct ctt gcc ggt atc ggt gac cct 2340 Gly Val Lys Val Gly Met Met Gly Pro Leu Ala Gly Ile Gly Asp Pro 690 695 700 gtc ttc tgg ttt aca gta cgt cct atc gtt ggt gcg att gca gct tca 2388 Val Phe Trp Phe Thr Val Arg Pro Ile Val Gly Ala Ile Ala Ala Ser 705 710 715 720 ttg gct act ggt gga tca att atc gct cca ctc ttc ttc ttc atc gtg 2436 Leu Ala Thr Gly Gly Ser Ile Ile Ala Pro Leu Phe Phe Phe Ile Val 725 730 735 tgg aac gct atc cgt atc gct ttc ttg tgg tac act caa gaa ttt ggt 2484 Trp Asn Ala Ile Arg Ile Ala Phe Leu Trp Tyr Thr Gln Glu Phe Gly 740 745 750 tat aaa tca ggt tct gca atc act aaa gac ctt ggt gga gga ctt ctc 2532 Tyr Lys Ser Gly Ser Ala Ile Thr Lys Asp Leu Gly Gly Gly Leu Leu 755 760 765 caa act gtt act aaa ggt gca tct atc ctt ggt atg ttc gtc ctt ggt 2580 Gln Thr Val Thr Lys Gly Ala Ser Ile Leu Gly Met Phe Val Leu Gly 770 775 780 gta ttg att caa cgt tgg gta aca att aac ttt aat ggt cct aac gct 2628 Val Leu Ile Gln Arg Trp Val Thr Ile Asn Phe Asn Gly Pro Asn Ala 785 790 795 800 gtt gtt tca aaa att cct tta caa aaa ggt gct tat cta gaa ttc cct 2676 Val Val Ser Lys Ile Pro Leu Gln Lys Gly Ala Tyr Leu Glu Phe Pro 805 810 815 aaa ggt tct gta tct ggt aca caa ctt cat gat att ctt ggt caa gtt 2724 Lys Gly Ser Val Ser Gly Thr Gln Leu His Asp Ile Leu Gly Gln Val 820 825 830 ggt aac aaa ctt tct ctt gat cct aca aaa gta act tac ctt caa gat 2772 Gly Asn Lys Leu Ser Leu Asp Pro Thr Lys Val Thr Tyr Leu Gln Asp 835 840 845 aac ttg aat caa ttg att cct ggt ctt gct ggt ttg ctt atc aca ttc 2820 Asn Leu Asn Gln Leu Ile Pro Gly Leu Ala Gly Leu Leu Ile Thr Phe 850 855 860 ctt tgc atg tgg ttg ctt aag aaa aaa gtt tct cca atc gtt att atc 2868 Leu Cys Met Trp Leu Leu Lys Lys Lys Val Ser Pro Ile Val Ile Ile 865 870 875 880 ttt ggt ctc ttc gtc gtg ggt atc ctc ggt cga tgg gct caa atc atg 2916 Phe Gly Leu Phe Val Val Gly Ile Leu Gly Arg Trp Ala Gln Ile Met 885 890 895 6 367 DNA Lactococcus lactis misc_feature (1)..(367) L. lactis MG1363 gene fragment whose product is homologous to a beta-glucosidase 6 gactttatta tctttcaaaa gttgataggt gtttttattt catctgttaa aattattgtt 60 tacttctagt tcagaagtaa gattttttat aaaatctgtt aaggaaattt cttagtaact 120 taaatcttct ccgtttgtcg aaatcacttt tttgtaccag tcaaagcccc gttttttgat 180 acgtttataa tctttatcta tataaacaaa accataacgt ttttcaaaac cttcacgagt 240 agagtaaagg tccgttgcag accatgtaag ataaccaatc atttctactc cctcttcaac 300 cgcttctttc atacgagcaa tatggtctgc taaatactta attctgtaat catcattaac 360 cgttccg 367 7 999 DNA Lactococcus lactis CDS (25)..(999) sequence of the L. lactis MG1363 gene whose product is homologous to a formate dehydrogenase 7 ttcattttat acaaaggagt ccca atg ata aaa gca att gcc tta gaa aat 51 Met Ile Lys Ala Ile Ala Leu Glu Asn 1 5 gtt tgg tta aat ttt tca gat gaa aca aaa gcg gct ttc aag aaa aat 99 Val Trp Leu Asn Phe Ser Asp Glu Thr Lys Ala Ala Phe Lys Lys Asn 10 15 20 25 aaa gct tac cag ttt caa ttt aaa aaa gaa gaa gag ctg aca gaa tca 147 Lys Ala Tyr Gln Phe Gln Phe Lys Lys Glu Glu Glu Leu Thr Glu Ser 30 35 40 gat ttt ctg gaa aca gaa gta tta gtt ggt ctg cca aag cct gat tta 195 Asp Phe Leu Glu Thr Glu Val Leu Val Gly Leu Pro Lys Pro Asp Leu 45 50 55 tta gca aaa tat aaa aat tta aaa tgg ctc caa ctt tta tca gct ggg 243 Leu Ala Lys Tyr Lys Asn Leu Lys Trp Leu Gln Leu Leu Ser Ala Gly 60 65 70 acc aat ggt tat act caa gga gca aat ttt cct caa gag gta gtt ttg 291 Thr Asn Gly Tyr Thr Gln Gly Ala Asn Phe Pro Gln Glu Val Val Leu 75 80 85 aca aat gca aca gga act tat gga ctt acg att tct gag cat tta cta 339 Thr Asn Ala Thr Gly Thr Tyr Gly Leu Thr Ile Ser Glu His Leu Leu 90 95 100 105 aca atg gct ttc gtt ctt cta aga aaa ttt gac ctt tat caa aaa caa 387 Thr Met Ala Phe Val Leu Leu Arg Lys Phe Asp Leu Tyr Gln Lys Gln 110 115 120 caa gaa aaa gaa atc tgg gaa aat att ggt cag att caa tct att tat 435 Gln Glu Lys Glu Ile Trp Glu Asn Ile Gly Gln Ile Gln Ser Ile Tyr 125 130 135 ggc tca aca gta ttg gtt cat ggt tta ggt gat att gga agt cac ttt 483 Gly Ser Thr Val Leu Val His Gly Leu Gly Asp Ile Gly Ser His Phe 140 145 150 gca caa aag att caa gct ttg gga ggt cat gtc att gca gtc aaa cga 531 Ala Gln Lys Ile Gln Ala Leu Gly Gly His Val Ile Ala Val Lys Arg 155 160 165 act gtt tat ggt gat gaa gaa ttt gct gat gaa gtc tat gcc gaa act 579 Thr Val Tyr Gly Asp Glu Glu Phe Ala Asp Glu Val Tyr Ala Glu Thr 170 175 180 185 gac cta gac aaa gtt tta ccg aga gct gat att att gct tca agt gtc 627 Asp Leu Asp Lys Val Leu Pro Arg Ala Asp Ile Ile Ala Ser Ser Val 190 195 200 cct ggg acc cat gaa act tat aaa tta ttt aat caa gaa aaa ttt gat 675 Pro Gly Thr His Glu Thr Tyr Lys Leu Phe Asn Gln Glu Lys Phe Asp 205 210 215 tta atg aaa gaa aat gct att ttc cta aat gtt ggt cgg gga aca aat 723 Leu Met Lys Glu Asn Ala Ile Phe Leu Asn Val Gly Arg Gly Thr Asn 220 225 230 gtc gat tta gaa gcc ttg tgt gat gct ctt gag tct aaa aaa att gct 771 Val Asp Leu Glu Ala Leu Cys Asp Ala Leu Glu Ser Lys Lys Ile Ala 235 240 245 ggg gca gga att gac gtg acc gac cca gaa cca ttg cct aaa ggt cac 819 Gly Ala Gly Ile Asp Val Thr Asp Pro Glu Pro Leu Pro Lys Gly His 250 255 260 265 cgg gct tgg cat aca gaa aga cta tta atc act cct cat gct tct ggc 867 Arg Ala Trp His Thr Glu Arg Leu Leu Ile Thr Pro His Ala Ser Gly 270 275 280 ggt tat act ctt cct gaa aca tgg cgt cgc ttt atg aaa ata ttg gaa 915 Gly Tyr Thr Leu Pro Glu Thr Trp Arg Arg Phe Met Lys Ile Leu Glu 285 290 295 aaa aat ctc gat gcc tat gca aat ggt aag gaa ttg aca aat att gtt 963 Lys Asn Leu Asp Ala Tyr Ala Asn Gly Lys Glu Leu Thr Asn Ile Val 300 305 310 gat atg aaa aca gga tat aaa cga aat gct cac aaa 999 Asp Met Lys Thr Gly Tyr Lys Arg Asn Ala His Lys 315 320 325 8 672 DNA Streptococcus thermophilus CDS (1)..(672) codY gene fragment 8 gat att att gat tgt aat gct gct att gta aat ggt gga ggt gct ctc 48 Asp Ile Ile Asp Cys Asn Ala Ala Ile Val Asn Gly Gly Gly Ala Leu 1 5 10 15 ctt ggt ttt gct atg aaa tac aaa acc aac aat gac cgt gtg gaa aag 96 Leu Gly Phe Ala Met Lys Tyr Lys Thr Asn Asn Asp Arg Val Glu Lys 20 25 30 ttt ttt aaa gct aaa caa ctt cca gag gaa tac ata cgt ggt atc agc 144 Phe Phe Lys Ala Lys Gln Leu Pro Glu Glu Tyr Ile Arg Gly Ile Ser 35 40 45 cgt gtt tat gat act caa gaa aat atc ggt att gac agt gac ttg acc 192 Arg Val Tyr Asp Thr Gln Glu Asn Ile Gly Ile Asp Ser Asp Leu Thr 50 55 60 atc ttc cca gtg gaa tta aaa gat gat ttc cct gac ggt ttg act aca 240 Ile Phe Pro Val Glu Leu Lys Asp Asp Phe Pro Asp Gly Leu Thr Thr 65 70 75 80 att gca cca atc tat ggt ggt ggt atg cgt ctt ggt tct ttc att att 288 Ile Ala Pro Ile Tyr Gly Gly Gly Met Arg Leu Gly Ser Phe Ile Ile 85 90 95 tgg cgt aac gac cat gat ttt gtg gac gac gac ctt atc ttg gtt gag 336 Trp Arg Asn Asp His Asp Phe Val Asp Asp Asp Leu Ile Leu Val Glu 100 105 110 att gca tct aca gta gtt ggt ttg caa ttg ttg cat ctt caa aca gaa 384 Ile Ala Ser Thr Val Val Gly Leu Gln Leu Leu His Leu Gln Thr Glu 115 120 125 aac ttg gaa gaa acg att cgt aaa caa aca gct att aat atg gct att 432 Asn Leu Glu Glu Thr Ile Arg Lys Gln Thr Ala Ile Asn Met Ala Ile 130 135 140 aat acc ttg tct tac tca gaa atc aag gca gtt tca gct atc ttg aat 480 Asn Thr Leu Ser Tyr Ser Glu Ile Lys Ala Val Ser Ala Ile Leu Asn 145 150 155 160 gag ttg gac ggt tta gaa ggt cgt ttg aca gcc tct gtt atc gcg gac 528 Glu Leu Asp Gly Leu Glu Gly Arg Leu Thr Ala Ser Val Ile Ala Asp 165 170 175 cgt atc gga att act cgt tct gtt att gtt aat gct ctt cgt aaa tta 576 Arg Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala Leu Arg Lys Leu 180 185 190 gaa tca gct ggt att att gaa agt cgt tcg ctt ggt atg aaa ggc act 624 Glu Ser Ala Gly Ile Ile Glu Ser Arg Ser Leu Gly Met Lys Gly Thr 195 200 205 tac ctc aaa gtc ctt aac gaa ggt atc tac gac aaa ttg aaa gaa tac 672 Tyr Leu Lys Val Leu Asn Glu Gly Ile Tyr Asp Lys Leu Lys Glu Tyr 210 215 220 9 783 DNA Streptococcus thermophilus CDS (1)..(783) full length codY 9 atg gca aat ttg ctt gat aaa aca cgt aaa att act tct atc ttg caa 48 Met Ala Asn Leu Leu Asp Lys Thr Arg Lys Ile Thr Ser Ile Leu Gln 1 5 10 15 cgc tca gta gat agt ttg gaa gga gat ctt cca tac aac aac atg gct 96 Arg Ser Val Asp Ser Leu Glu Gly Asp Leu Pro Tyr Asn Asn Met Ala 20 25 30 gct cag ttg gca gat att att gat tgt aat gct gct att gta aat ggt 144 Ala Gln Leu Ala Asp Ile Ile Asp Cys Asn Ala Ala Ile Val Asn Gly 35 40 45 gga ggt gct ctc ctt ggt ttt gct atg aaa tac aaa acc aac aat gac 192 Gly Gly Ala Leu Leu Gly Phe Ala Met Lys Tyr Lys Thr Asn Asn Asp 50 55 60 cgt gtg gaa aag ttt ttt aaa gct aaa caa ctt cca gag gaa tac ata 240 Arg Val Glu Lys Phe Phe Lys Ala Lys Gln Leu Pro Glu Glu Tyr Ile 65 70 75 80 cgt ggt atc agc cgt gtt tat gat act caa gaa aat atc ggt att gac 288 Arg Gly Ile Ser Arg Val Tyr Asp Thr Gln Glu Asn Ile Gly Ile Asp 85 90 95 agt gac ttg acc atc ttc cca gtg gaa tta aaa gat gat ttc cct gac 336 Ser Asp Leu Thr Ile Phe Pro Val Glu Leu Lys Asp Asp Phe Pro Asp 100 105 110 ggt ttg act aca att gca cca atc tat ggt ggt ggt atg cgt ctt ggt 384 Gly Leu Thr Thr Ile Ala Pro Ile Tyr Gly Gly Gly Met Arg Leu Gly 115 120 125 tct ttc att att tgg cgt aac gac cat gat ttt gtg gac gac gac ctt 432 Ser Phe Ile Ile Trp Arg Asn Asp His Asp Phe Val Asp Asp Asp Leu 130 135 140 atc ttg gtt gag att gca tct aca gta gtt ggt ttg caa ttg ttg cat 480 Ile Leu Val Glu Ile Ala Ser Thr Val Val Gly Leu Gln Leu Leu His 145 150 155 160 ctt caa aca gaa aac ttg gaa gaa acg att cgt aaa caa aca gct att 528 Leu Gln Thr Glu Asn Leu Glu Glu Thr Ile Arg Lys Gln Thr Ala Ile 165 170 175 aat atg gct att aat acc ttg tct tac tca gaa atc aag gca gtt tca 576 Asn Met Ala Ile Asn Thr Leu Ser Tyr Ser Glu Ile Lys Ala Val Ser 180 185 190 gct atc ttg aat gag ttg gac ggt tta gaa ggt cgt ttg aca gcc tct 624 Ala Ile Leu Asn Glu Leu Asp Gly Leu Glu Gly Arg Leu Thr Ala Ser 195 200 205 gtt atc gcg gac cgt atc gga att act cgt tct gtt att gtt aat gct 672 Val Ile Ala Asp Arg Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala 210 215 220 ctt cgt aaa tta gaa tca gct ggt att att gaa agt cgt tcg ctt ggt 720 Leu Arg Lys Leu Glu Ser Ala Gly Ile Ile Glu Ser Arg Ser Leu Gly 225 230 235 240 atg aaa ggc act tac ctt aaa gtc ctt aac gaa ggt atc tac gac aaa 768 Met Lys Gly Thr Tyr Leu Lys Val Leu Asn Glu Gly Ile Tyr Asp Lys 245 250 255 ttg aaa gaa tac gaa 783 Leu Lys Glu Tyr Glu 260 10 259 PRT Lactococcus lactis 10 Leu Leu Glu Lys Thr Arg Lys Ile Thr Ala Ile Leu Gln Asp Gly Val 1 5 10 15 Thr Asp Leu Gln Gln Glu Leu Pro Tyr Asn Ser Met Thr Glu Arg Leu 20 25 30 Ala Asn Val Ile Asp Cys Asn Ala Cys Val Ile Asn Thr Lys Gly Glu 35 40 45 Leu Leu Gly Tyr Ser Leu Pro Tyr Asn Thr Asn Asn Asp Arg Val Asp 50 55 60 Gln Phe Phe Tyr Asp Arg Lys Leu Pro Asp Glu Tyr Val Arg Ala Ala 65 70 75 80 Val Arg Ile Tyr Asp Thr Met Ala Asn Val Pro Val Asp Arg Pro Leu 85 90 95 Ala Ile Phe Pro Glu Glu Ser Leu Ser Asp Phe Pro Lys Gly Val Thr 100 105 110 Thr Leu Ala Pro Ile Tyr Gly Ser Gly Met Arg Leu Gly Thr Phe Ile 115 120 125 Met Trp Arg Glu Asp Gly Glu Phe Thr Asp Asp Asp Leu Val Leu Val 130 135 140 Glu Leu Ala Thr Thr Val Ile Gly Val Gln Leu Ser Asn Leu Lys Leu 145 150 155 160 Glu Gln Met Glu Glu Asn Ile Arg Lys Asp Thr Met Ala Thr Met Ala 165 170 175 Val Asn Thr Leu Ser Tyr Ser Glu Met Lys Ala Val Lys Ala Ile Ile 180 185 190 Glu Glu Leu Asp Gly Glu Glu Gly His Val Ile Ala Ser Val Ile Ala 195 200 205 Asp Lys Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala Leu Arg Lys 210 215 220 Leu Glu Ser Ala Gly Val Ile Glu Ser Arg Ser Leu Gly Met Lys Gly 225 230 235 240 Thr Tyr Leu Lys Val Leu Asn Thr Gly Leu Phe Asp Lys Leu Ala Gly 245 250 255 Arg Asn Phe 11 463 PRT Lactococcus lactis 11 Met Arg Ala Ile Leu Val Tyr Tyr Leu Tyr Ala Leu Thr Thr Ala Asp 1 5 10 15 Asn Ala Gly Leu Gly Leu Pro Lys Ala Gln Ala Met Ala Ile Val Ser 20 25 30 Ile Tyr Gly Ala Leu Val Tyr Leu Ser Thr Ile Val Gly Gly Trp Val 35 40 45 Ala Asp Arg Leu Leu Gly Ala Ser Arg Thr Ile Phe Leu Gly Gly Ile 50 55 60 Leu Ile Thr Leu Gly His Val Ala Leu Ala Thr Pro Phe Gly Leu Ser 65 70 75 80 Ser Leu Phe Val Ala Leu Phe Leu Ile Ile Leu Gly Thr Gly Met Leu 85 90 95 Lys Pro Asn Ile Ser Asn Met Val Gly His Leu Tyr Ser Lys Asp Asp 100 105 110 Ser Arg Arg Asp Thr Gly Phe Asn Ile Phe Val Val Gly Ile Asn Met 115 120 125 Gly Ser Leu Ile Ala Pro Leu Ile Val Gly Thr Val Gly Gln Gly Val 130 135 140 Asn Tyr His Leu Gly Phe Ser Leu Ala Ala Ile Gly Met Ile Phe Ala 145 150 155 160 Leu Phe Ala Tyr Trp Tyr Gly Arg Leu Arg His Phe Pro Glu Ile Gly 165 170 175 Arg Glu Pro Ser Asn Pro Met Asp Ala Lys Ala Lys Arg Asn Phe Ile 180 185 190 Ile Thr Leu Thr Ile Val Leu Ile Val Ala Leu Ile Gly Phe Phe Leu 195 200 205 Ile Tyr Gln Ala Ser Pro Ala Asn Phe Ile Asn Asn Phe Ile Asn Val 210 215 220 Leu Ser Ile Ile Gly Ile Val Val Pro Ile Ile Tyr Phe Val Met Met 225 230 235 240 Phe Thr Ser Lys Lys Val Glu Ser Asp Glu Arg Arg Lys Leu Thr Ala 245 250 255 Tyr Ile Pro Leu Phe Leu Ser Ala Ile Val Phe Trp Ala Ile Glu Glu 260 265 270 Gln Ser Ser Thr Ile Ile Ala Val Trp Gly Glu Ser Arg Ser Asn Leu 275 280 285 Asn Pro Thr Trp Phe Gly Phe Thr Phe His Ile Asp Pro Ser Trp Tyr 290 295 300 Gln Leu Leu Asn Pro Leu Phe Ile Val Leu Leu Ser Pro Ile Phe Val 305 310 315 320 Arg Ile Trp Asn Lys Leu Gly Asp Arg Gln Pro Ser Thr Ile Val Lys 325 330 335 Phe Gly Leu Gly Leu Met Leu Thr Gly Ala Ser Tyr Leu Ile Met Thr 340 345 350 Leu Pro Gly Leu Leu Asn Gly Thr Ser Gly Arg Ala Ser Ala Leu Trp 355 360 365 Leu Val Leu Met Phe Ala Val Gln Met Ala Gly Glu Leu Leu Val Ser 370 375 380 Pro Val Gly Leu Ser Val Ser Thr Lys Leu Ala Pro Val Ala Phe Gln 385 390 395 400 Ser Gln Met Met Ala Met Trp Phe Leu Ala Asp Ser Thr Ser Gln Ala 405 410 415 Ile Asn Ala Gln Ile Thr Pro Ile Phe Lys Ala Ala Thr Glu Val His 420 425 430 Phe Phe Ala Ile Thr Gly Ile Ile Gly Ile Ile Val Gly Ile Ile Leu 435 440 445 Leu Ile Ile Lys Lys Pro Ile Leu Lys Leu Met Gly Asp Val Arg 450 455 460 12 573 PRT Lactococcus lactis 12 Met Glu Asn Val Ala Leu Thr His Phe Val Asp Asn Ala Leu Arg Ala 1 5 10 15 Asn Phe Ile Met Leu His Asp Ile Asp Tyr Met Val Asp Glu Asn Gln 20 25 30 Glu Val Leu Ile Ile Asp Gln Phe Thr Gly Arg Thr Met Pro Gly Arg 35 40 45 Arg Tyr Ser Asp Gly Leu His Gln Ala Ile Glu Ala Lys Glu Ala Val 50 55 60 Pro Ile Gln Asp Glu Ser Lys Thr Met Ala Ser Ile Thr Ile Gln Asn 65 70 75 80 Tyr Phe Arg Met Tyr Lys Lys Leu Ser Gly Met Thr Gly Thr Ala Lys 85 90 95 Thr Glu Glu Glu Glu Phe Arg Glu Ile Tyr Asn Ile Gln Ile Thr Pro 100 105 110 Ile Pro Thr Asn Arg Pro Val Gln Arg Leu Asp His Pro Asp Leu Leu 115 120 125 Tyr Pro Thr Leu Glu Ala Lys Phe Lys Ala Val Ile Asp Asp Ile Lys 130 135 140 Arg Arg His Ala Glu Gly Gln Pro Ile Leu Ile Gly Thr Val Ala Val 145 150 155 160 Glu Thr Ser Glu Leu Ile Ser Lys Lys Leu Val Glu Ala Lys Ile Pro 165 170 175 His Glu Val Leu Asn Ala Lys Asn His Phe Arg Glu Ala Gln Ile Ile 180 185 190 Met Asn Ala Gly Gln Gln Gly Ala Val Thr Ile Ala Thr Asn Met Ala 195 200 205 Gly Arg Gly Thr Asp Ile Lys Leu Gly Pro Gly Val Ile Asp His Val 210 215 220 Asp Pro Glu Phe Arg Gly Leu Ala Val Ile Gly Thr Glu Arg His Glu 225 230 235 240 Ser Arg Arg Ile Asp Asn Gln Leu Arg Gly Arg Ser Gly Arg Gln Gly 245 250 255 Asp Pro Gly Val Ser Gln Phe Tyr Leu Ser Leu Glu Asp Glu Leu Met 260 265 270 Lys Arg Phe Gly Ser Glu Arg Val Ser Ala Phe Leu Asp Arg Met Arg 275 280 285 Ile Ser Gly Glu Asp Ala Val Ile Lys Ser Gly Leu Ile Thr Arg Gln 290 295 300 Ile Glu Ser Ser Gln Lys Arg Val Glu Gly Asn Asn Tyr Asp Ser Arg 305 310 315 320 Lys Gln Val Leu Gln Tyr Asp Asp Val Ile Arg Glu Gln Arg Glu Val 325 330 335 Ile Tyr Ala Gln Arg Gln Glu Val Ile Leu Ala Thr Glu Asp Met Thr 340 345 350 Pro Val Leu Met Gly Met Phe Lys Arg Thr Ile Asp Arg Gln Val Asp 355 360 365 Gly His Glu Leu Ala Gly Ser Leu Lys Asp Glu Glu Asn Val Lys Asn 370 375 380 Leu Leu Gln Thr Leu His Asn Thr Met Leu Pro Glu Asp Gly Ile Glu 385 390 395 400 Leu Ser Glu Leu Thr Gly Leu Ser Val Gln Ala Met Lys Asp Leu Ile 405 410 415 Phe Asp Lys Val Lys Ala Arg Tyr Ala Ser Gln Met Glu Lys Leu Ser 420 425 430 Asp Pro Glu Arg Gln Leu Glu Phe Gln Arg Ala Val Ile Leu Arg Val 435 440 445 Val Asp Asn Asn Trp Ser Glu His Ile Asp Ala Leu Asp Gln Met Arg 450 455 460 Gln Ser Val Gly Leu Arg Gly Tyr Ala Gln Asn Asn Pro Ile Val Glu 465 470 475 480 Tyr Gln Glu Glu Ser Tyr Lys Met Tyr Asn Asn Met Ile Gly Ala Ile 485 490 495 Glu Phe Glu Val Thr Arg Leu Met Met Lys Ala Gln Ile Gln Pro Gln 500 505 510 Thr Ala Ile Arg Gln Glu Ala Pro Arg Met Thr Thr Thr Ala Ser Gln 515 520 525 Glu Asn Ile Thr Asn Val Asp Thr Glu His Ser Val Ser Glu Glu Ile 530 535 540 Ser Phe Glu Asn Val Gly Arg Asn Asp Leu Cys Pro Cys Gly Ser Gly 545 550 555 560 Lys Lys Phe Lys Asn Cys His Gly Arg Thr His Ile Ala 565 570 13 439 PRT Lactococcus lactis 13 Met Phe Phe Lys Thr Leu Lys Glu Ala Phe Lys Val Lys Asp Val Arg 1 5 10 15 Ala Arg Ile Leu Phe Thr Ile Phe Ile Leu Phe Val Phe Arg Leu Gly 20 25 30 Ala His Ile Thr Val Pro Gly Val Asn Val Gln Asn Leu Thr Glu Val 35 40 45 Ser Asn Leu Pro Phe Leu Asn Met Met Asn Leu Val Ser Gly Asn Ala 50 55 60 Met Gln Asn Tyr Ser Leu Phe Ala Met Gly Val Ser Pro Tyr Ile Thr 65 70 75 80 Ala Ser Ile Ile Val Gln Leu Leu Gln Met Asp Ile Leu Pro Lys Phe 85 90 95 Val Glu Trp Ser Lys Gln Gly Glu Ile Gly Arg Arg Lys Leu Asn Gln 100 105 110 Ala Thr Arg Tyr Ile Thr Leu Val Leu Ala Met Ala Gln Ser Ile Gly 115 120 125 Ile Thr Ala Gly Phe Gln Ala Met Ser Ser Leu Asn Ile Val Gln Asn 130 135 140 Pro Asn Trp Gln Ser Tyr Leu Met Ile Gly Ala Ile Leu Thr Thr Gly 145 150 155 160 Ser Met Val Val Thr Trp Met Gly Glu Gln Ile Asn Asp Gln Gly Phe 165 170 175 Gly Ser Gly Val Ser Val Ile Ile Phe Ala Gly Ile Val Ser Ser Ile 180 185 190 Pro Ser Ala Ile Lys Ser Val Tyr Asp Glu Lys Phe Leu Asn Val Arg 195 200 205 Pro Ser Glu Ile Pro Met Ser Trp Ile Phe Val Ile Gly Leu Ile Leu 210 215 220 Ser Ala Ile Val Ile Ile Tyr Val Thr Thr Phe Val Gln Gln Ala Glu 225 230 235 240 Arg Lys Val Pro Ile Gln Tyr Thr Lys Leu Thr Gln Gly Ala Pro Thr 245 250 255 Ser Ser Tyr Phe Pro Leu Arg Val Asn Pro Ala Gly Val Ile Pro Val 260 265 270 Ile Phe Ala Gly Ser Ile Thr Thr Ala Pro Ala Thr Ile Leu Gln Phe 275 280 285 Leu Gln Arg Ser Gln Gly Ser Asn Val Gly Trp Leu Ser Thr Leu Gln 290 295 300 Asn Ala Leu Ser Tyr Thr Thr Trp Thr Gly Met Leu Phe Tyr Ala Leu 305 310 315 320 Leu Ile Val Leu Phe Thr Phe Phe Tyr Ser Phe Val Gln Val Asn Pro 325 330 335 Glu Lys Met Ala Glu Asn Leu Gln Lys Gln Gly Ser Tyr Ile Pro Ser 340 345 350 Val Arg Pro Gly Lys Gly Thr Glu Lys Tyr Val Ser Arg Leu Leu Met 355 360 365 Arg Leu Ala Thr Val Gly Ser Leu Phe Leu Gly Leu Ile Ser Ile Ile 370 375 380 Pro Ile Ala Ala Gln Asn Val Trp Gly Leu Pro Lys Ile Val Ala Leu 385 390 395 400 Gly Gly Thr Ser Leu Leu Ile Leu Ile Gln Val Ala Ile Gln Ala Val 405 410 415 Lys Gln Leu Glu Gly Tyr Leu Leu Lys Arg Lys Tyr Ala Gly Phe Met 420 425 430 Asp Asn Pro Leu Glu Thr Lys 435 14 319 PRT Lactococcus lactis 14 Met Val Asn Ser Pro Gln Ile Lys Gln Ser Gly Ser Met Ile Phe Gly 1 5 10 15 Glu Gln Glu Lys Val Gln Val Val Thr Phe Met Pro Ser Glu Gly Pro 20 25 30 Thr Asp Leu His Ala Lys Ile Glu Ala Ala Ile Ala Thr Phe Asp Ala 35 40 45 Glu Asp Glu Val Leu Val Leu Ala Asp Leu Trp Ser Gly Ser Pro Phe 50 55 60 Asn Gln Ala Ser Ala Val Met Gly Glu Asn Pro Glu Arg Lys Ile Ala 65 70 75 80 Ile Ile Thr Gly Leu Asn Leu Pro Met Leu Ile Gln Ala Tyr Thr Glu 85 90 95 Arg Met Met Asp Ala Ser Ala Gly Val Asp Lys Val Val Ala Asn Ile 100 105 110 Met Lys Glu Ala Lys Gly Gly Ile Lys Val Leu Pro Glu Glu Leu Gln 115 120 125 Pro Ala Glu Glu Thr Ala Val Ala Ala Ala Pro Ala Ala Val Gln Gly 130 135 140 Ala Ile Pro Glu Gly Thr Val Ile Gly Asp Gly Lys Ile Lys Ile Asn 145 150 155 160 Leu Ala Arg Ile Asp Ser Arg Leu Leu His Gly Gln Val Ala Thr Ala 165 170 175 Trp Thr Pro Asp Ser Arg Ala Asn Arg Ile Ile Val Val Ser Asp Thr 180 185 190 Val Ser Lys Asp Glu Leu Arg Lys Lys Leu Ile Glu Gln Ala Ala Pro 195 200 205 Thr Gly Val Lys Ala Asn Val Ile Pro Ile Lys Lys Met Ile Glu Val 210 215 220 Ala Lys Asp Pro Arg Phe Gly Asp Thr Lys Ala Leu Leu Leu Phe Glu 225 230 235 240 Thr Pro Gln Asp Ala Leu Ala Thr Ile Glu Gly Gly Val Pro Ile Glu 245 250 255 Thr Leu Asn Val Gly Ser Met Ala His Ser Thr Gly Lys Thr Met Leu 260 265 270 Asn Lys Val Leu Ser Met Asp Lys Asp Asp Val Ala Thr Phe Glu Lys 275 280 285 Leu Arg Asp Leu Gly Val Lys Phe Asp Val Arg Lys Val Pro Ala Asp 290 295 300 Ser Lys Ser Asp Leu Phe Gly Leu Ile Asn Lys Ala Asp Val Gln 305 310 315 15 270 PRT Lactococcus lactis 15 Met Glu Tyr Gly Val Leu Ser Val Ile Leu Val Ile Val Val Ala Phe 1 5 10 15 Leu Ala Gly Leu Glu Gly Ile Leu Asp Gln Trp Gln Phe His Gln Pro 20 25 30 Ile Ile Ala Cys Ser Leu Ile Gly Ile Val Thr Gly His Ala Ser Ala 35 40 45 Gly Ile Ile Leu Gly Gly Ser Leu Gln Leu Ile Ala Leu Gly Trp Ala 50 55 60 Asn Val Gly Ala Ala Val Ala Pro Asp Ala Ala Leu Ala Ser Ile Ala 65 70 75 80 Ser Ser Ile Leu Met Val Gln Ser Asn Asn Phe Asp Leu Thr His Ile 85 90 95 Met Gly Thr Ile Val Pro Ala Ala Ile Leu Leu Ala Thr Ala Gly Leu 100 105 110 Val Leu Thr Thr Leu Val Arg Met Leu Ser Val Val Leu Val His Gln 115 120 125 Ala Asp Arg Ala Ala Glu Asn Gly Ser Tyr Ser Gly Val Glu Met Trp 130 135 140 His Phe Ile Ala Leu Ile Cys Gln Gly Leu Arg Ile Ala Ile Pro Ala 145 150 155 160 Gly Leu Leu Leu Val Ile Ser Pro Asp Ala Ile Gln Lys Ala Leu Ala 165 170 175 Ala Ile Pro Pro Val Ile Ser Gly Gly Leu Ala Val Gly Gly Gly Met 180 185 190 Val Val Ala Val Gly Tyr Ala Met Val Ile Asn Leu Met Ala Thr Arg 195 200 205 Glu Val Trp Pro Phe Phe Phe Leu Gly Phe Ala Leu Ala Pro Ile Ser 210 215 220 Glu Leu Thr Leu Ile Ala Thr Gly Val Leu Gly Val Val Ile Ala Ile 225 230 235 240 Val Tyr Leu Asn Leu Gln Ala Ser Gly Gly Ser Gly Asn Gly Thr Ala 245 250 255 Ser Ser Ser Gly Asp Pro Ile Gly Asp Ile Leu Asn Asp Tyr 260 265 270 16 307 PRT Lactococcus lactis 16 Met Ser Glu Asn Lys Val Thr Leu Asp Lys Lys Ile Arg Arg Ser Val 1 5 10 15 Met Trp Arg Ser Met Phe Leu Gln Gly Ser Trp Asn Tyr Glu Arg Met 20 25 30 Gln Asn Gly Gly Trp Ala Tyr Ser Leu Ile Pro Ala Leu Lys Lys Leu 35 40 45 Tyr Pro Ser Gly Glu Glu Ala Lys Glu Ala Leu Lys Arg His Leu Glu 50 55 60 Phe Phe Asn Thr His Pro Tyr Val Ala Ala Pro Ile Ile Gly Val Thr 65 70 75 80 Leu Ala Leu Glu Glu Glu Arg Ala Asn Gly Ala Asp Ile Asp Asp Ala 85 90 95 Ala Ile Gln Gly Val Lys Val Gly Met Met Gly Pro Leu Ala Gly Ile 100 105 110 Gly Asp Pro Val Phe Trp Phe Thr Val Arg Pro Ile Val Gly Ala Ile 115 120 125 Ala Ala Ser Leu Ala Thr Gly Gly Ser Ile Ile Ala Pro Leu Phe Phe 130 135 140 Phe Ile Val Trp Asn Ala Ile Arg Ile Ala Phe Leu Trp Tyr Thr Gln 145 150 155 160 Glu Phe Gly Tyr Lys Ser Gly Ser Ala Ile Thr Lys Asp Leu Gly Gly 165 170 175 Gly Leu Leu Gln Thr Val Thr Lys Gly Ala Ser Ile Leu Gly Met Phe 180 185 190 Val Leu Gly Val Leu Ile Gln Arg Trp Val Thr Ile Asn Phe Asn Gly 195 200 205 Pro Asn Ala Val Val Ser Lys Ile Pro Leu Gln Lys Gly Ala Tyr Leu 210 215 220 Glu Phe Pro Lys Gly Ser Val Ser Gly Thr Gln Leu His Asp Ile Leu 225 230 235 240 Gly Gln Val Gly Asn Lys Leu Ser Leu Asp Pro Thr Lys Val Thr Tyr 245 250 255 Leu Gln Asp Asn Leu Asn Gln Leu Ile Pro Gly Leu Ala Gly Leu Leu 260 265 270 Ile Thr Phe Leu Cys Met Trp Leu Leu Lys Lys Lys Val Ser Pro Ile 275 280 285 Val Ile Ile Phe Gly Leu Phe Val Val Gly Ile Leu Gly Arg Trp Ala 290 295 300 Gln Ile Met 305 17 325 PRT Lactococcus lactis 17 Met Ile Lys Ala Ile Ala Leu Glu Asn Val Trp Leu Asn Phe Ser Asp 1 5 10 15 Glu Thr Lys Ala Ala Phe Lys Lys Asn Lys Ala Tyr Gln Phe Gln Phe 20 25 30 Lys Lys Glu Glu Glu Leu Thr Glu Ser Asp Phe Leu Glu Thr Glu Val 35 40 45 Leu Val Gly Leu Pro Lys Pro Asp Leu Leu Ala Lys Tyr Lys Asn Leu 50 55 60 Lys Trp Leu Gln Leu Leu Ser Ala Gly Thr Asn Gly Tyr Thr Gln Gly 65 70 75 80 Ala Asn Phe Pro Gln Glu Val Val Leu Thr Asn Ala Thr Gly Thr Tyr 85 90 95 Gly Leu Thr Ile Ser Glu His Leu Leu Thr Met Ala Phe Val Leu Leu 100 105 110 Arg Lys Phe Asp Leu Tyr Gln Lys Gln Gln Glu Lys Glu Ile Trp Glu 115 120 125 Asn Ile Gly Gln Ile Gln Ser Ile Tyr Gly Ser Thr Val Leu Val His 130 135 140 Gly Leu Gly Asp Ile Gly Ser His Phe Ala Gln Lys Ile Gln Ala Leu 145 150 155 160 Gly Gly His Val Ile Ala Val Lys Arg Thr Val Tyr Gly Asp Glu Glu 165 170 175 Phe Ala Asp Glu Val Tyr Ala Glu Thr Asp Leu Asp Lys Val Leu Pro 180 185 190 Arg Ala Asp Ile Ile Ala Ser Ser Val Pro Gly Thr His Glu Thr Tyr 195 200 205 Lys Leu Phe Asn Gln Glu Lys Phe Asp Leu Met Lys Glu Asn Ala Ile 210 215 220 Phe Leu Asn Val Gly Arg Gly Thr Asn Val Asp Leu Glu Ala Leu Cys 225 230 235 240 Asp Ala Leu Glu Ser Lys Lys Ile Ala Gly Ala Gly Ile Asp Val Thr 245 250 255 Asp Pro Glu Pro Leu Pro Lys Gly His Arg Ala Trp His Thr Glu Arg 260 265 270 Leu Leu Ile Thr Pro His Ala Ser Gly Gly Tyr Thr Leu Pro Glu Thr 275 280 285 Trp Arg Arg Phe Met Lys Ile Leu Glu Lys Asn Leu Asp Ala Tyr Ala 290 295 300 Asn Gly Lys Glu Leu Thr Asn Ile Val Asp Met Lys Thr Gly Tyr Lys 305 310 315 320 Arg Asn Ala His Lys 325 18 224 PRT Streptococcus thermophilus 18 Asp Ile Ile Asp Cys Asn Ala Ala Ile Val Asn Gly Gly Gly Ala Leu 1 5 10 15 Leu Gly Phe Ala Met Lys Tyr Lys Thr Asn Asn Asp Arg Val Glu Lys 20 25 30 Phe Phe Lys Ala Lys Gln Leu Pro Glu Glu Tyr Ile Arg Gly Ile Ser 35 40 45 Arg Val Tyr Asp Thr Gln Glu Asn Ile Gly Ile Asp Ser Asp Leu Thr 50 55 60 Ile Phe Pro Val Glu Leu Lys Asp Asp Phe Pro Asp Gly Leu Thr Thr 65 70 75 80 Ile Ala Pro Ile Tyr Gly Gly Gly Met Arg Leu Gly Ser Phe Ile Ile 85 90 95 Trp Arg Asn Asp His Asp Phe Val Asp Asp Asp Leu Ile Leu Val Glu 100 105 110 Ile Ala Ser Thr Val Val Gly Leu Gln Leu Leu His Leu Gln Thr Glu 115 120 125 Asn Leu Glu Glu Thr Ile Arg Lys Gln Thr Ala Ile Asn Met Ala Ile 130 135 140 Asn Thr Leu Ser Tyr Ser Glu Ile Lys Ala Val Ser Ala Ile Leu Asn 145 150 155 160 Glu Leu Asp Gly Leu Glu Gly Arg Leu Thr Ala Ser Val Ile Ala Asp 165 170 175 Arg Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala Leu Arg Lys Leu 180 185 190 Glu Ser Ala Gly Ile Ile Glu Ser Arg Ser Leu Gly Met Lys Gly Thr 195 200 205 Tyr Leu Lys Val Leu Asn Glu Gly Ile Tyr Asp Lys Leu Lys Glu Tyr 210 215 220 19 261 PRT Streptococcus thermophilus 19 Met Ala Asn Leu Leu Asp Lys Thr Arg Lys Ile Thr Ser Ile Leu Gln 1 5 10 15 Arg Ser Val Asp Ser Leu Glu Gly Asp Leu Pro Tyr Asn Asn Met Ala 20 25 30 Ala Gln Leu Ala Asp Ile Ile Asp Cys Asn Ala Ala Ile Val Asn Gly 35 40 45 Gly Gly Ala Leu Leu Gly Phe Ala Met Lys Tyr Lys Thr Asn Asn Asp 50 55 60 Arg Val Glu Lys Phe Phe Lys Ala Lys Gln Leu Pro Glu Glu Tyr Ile 65 70 75 80 Arg Gly Ile Ser Arg Val Tyr Asp Thr Gln Glu Asn Ile Gly Ile Asp 85 90 95 Ser Asp Leu Thr Ile Phe Pro Val Glu Leu Lys Asp Asp Phe Pro Asp 100 105 110 Gly Leu Thr Thr Ile Ala Pro Ile Tyr Gly Gly Gly Met Arg Leu Gly 115 120 125 Ser Phe Ile Ile Trp Arg Asn Asp His Asp Phe Val Asp Asp Asp Leu 130 135 140 Ile Leu Val Glu Ile Ala Ser Thr Val Val Gly Leu Gln Leu Leu His 145 150 155 160 Leu Gln Thr Glu Asn Leu Glu Glu Thr Ile Arg Lys Gln Thr Ala Ile 165 170 175 Asn Met Ala Ile Asn Thr Leu Ser Tyr Ser Glu Ile Lys Ala Val Ser 180 185 190 Ala Ile Leu Asn Glu Leu Asp Gly Leu Glu Gly Arg Leu Thr Ala Ser 195 200 205 Val Ile Ala Asp Arg Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala 210 215 220 Leu Arg Lys Leu Glu Ser Ala Gly Ile Ile Glu Ser Arg Ser Leu Gly 225 230 235 240 Met Lys Gly Thr Tyr Leu Lys Val Leu Asn Glu Gly Ile Tyr Asp Lys 245 250 255 Leu Lys Glu Tyr Glu 260 20 259 PRT Lactococcus lactis 20 Leu Leu Glu Lys Thr Arg Lys Ile Thr Ala Ile Leu Gln Asp Gly Val 1 5 10 15 Thr Asp Leu Gln Gln Glu Leu Pro Tyr Asn Ser Met Thr Glu Arg Leu 20 25 30 Ala Asn Val Ile Asp Cys Asn Ala Cys Val Ile Asn Thr Lys Gly Glu 35 40 45 Leu Leu Gly Tyr Ser Leu Pro Tyr Asn Thr Asn Asn Asp Arg Val Asp 50 55 60 Gln Phe Phe Tyr Asp Arg Lys Leu Pro Asp Glu Tyr Val Arg Ala Ala 65 70 75 80 Val Arg Ile Tyr Asp Thr Met Ala Asn Val Pro Val Asp Arg Pro Leu 85 90 95 Ala Ile Phe Pro Glu Glu Ser Leu Ser Asp Phe Pro Lys Gly Val Thr 100 105 110 Thr Leu Ala Pro Ile Tyr Gly Ser Gly Met Arg Leu Gly Thr Phe Ile 115 120 125 Met Trp Arg Glu Asp Gly Glu Phe Thr Asp Asp Asp Leu Val Leu Val 130 135 140 Glu Leu Ala Thr Thr Val Ile Gly Val Gln Leu Ser Asn Leu Lys Leu 145 150 155 160 Glu Gln Met Glu Glu Asn Ile Arg Lys Asp Thr Met Ala Thr Met Ala 165 170 175 Val Asn Thr Leu Ser Tyr Ser Glu Met Lys Ala Val Lys Ala Ile Ile 180 185 190 Glu Glu Leu Asp Gly Glu Glu Gly His Val Ile Ala Ser Val Ile Ala 195 200 205 Asp Lys Ile Gly Ile Thr Arg Ser Val Ile Val Asn Ala Leu Arg Lys 210 215 220 Leu Glu Ser Ala Gly Val Ile Glu Ser Arg Ser Leu Gly Met Lys Gly 225 230 235 240 Thr Tyr Leu Lys Val Leu Asn Thr Gly Leu Phe Asp Lys Leu Ala Gly 245 250 255 Arg Asn Phe 21 258 PRT Bacillus subtilis 21 Ala Leu Leu Gln Lys Thr Arg Ile Ile Asn Ser Met Leu Gln Ala Ala 1 5 10 15 Ala Gly Lys Pro Val Asn Phe Lys Glu Met Ala Glu Thr Leu Arg Asp 20 25 30 Val Ile Asp Ser Asn Ile Phe Val Val Ser Arg Arg Gly Lys Leu Leu 35 40 45 Gly Tyr Ser Ile Asn Gln Gln Ile Glu Asn Asp Arg Met Lys Lys Met 50 55 60 Leu Glu Asp Arg Gln Phe Pro Glu Glu Tyr Thr Lys Asn Leu Phe Asn 65 70 75 80 Val Pro Glu Thr Ser Ser Asn Leu Asp Ile Asn Ser Glu Tyr Thr Ala 85 90 95 Phe Pro Val Glu Asn Arg Asp Leu Phe Gln Ala Gly Leu Thr Thr Ile 100 105 110 Val Pro Ile Ile Gly Gly Gly Glu Arg Leu Gly Thr Leu Ile Leu Ser 115 120 125 Arg Leu Gln Asp Gln Phe Asn Asp Asp Asp Leu Ile Leu Ala Glu Tyr 130 135 140 Gly Ala Thr Val Val Gly Met Glu Ile Leu Arg Glu Lys Ala Glu Glu 145 150 155 160 Ile Glu Glu Glu Ala Arg Ser Lys Ala Val Val Gln Met Ala Ile Ser 165 170 175 Ser Leu Ser Tyr Ser Glu Leu Glu Ala Ile Glu His Ile Phe Glu Glu 180 185 190 Leu Asp Gly Asn Glu Gly Leu Leu Val Ala Ser Lys Ile Ala Asp Arg 195 200 205 Val Gly Ile Thr Arg Ser Val Ile Val Asn Ala Leu Arg Lys Leu Glu 210 215 220 Ser Ala Gly Val Ile Glu Ser Arg Ser Leu Gly Met Lys Gly Thr Tyr 225 230 235 240 Ile Lys Val Leu Asn Asn Lys Phe Leu Ile Glu Leu Glu Asn Leu Lys 245 250 255 Ser His 22 25 DNA Artificial Sequence Description of Artificial Sequence Primer 22 gggaattctt tgggaacaat gataa 25 23 23 DNA Artificial Sequence Description of Artificial Sequence Primer 23 cgggatccgt tacttctgaa cca 23 24 21 DNA Artificial Sequence Description of Artificial Sequence Synthetic oligonucleotide 24 tcacctcata taaattcccc a 21 25 18 DNA Artificial Sequence Description of Artificial Sequence Synthetic oligonucleotide 25 aaatggaacg ctcttcgg 18 26 24 DNA Artificial Sequence Description of Artificial Sequence Synthetic oligonucleotide 26 cgccagggtt ttcccagtca cgac 24 27 22 DNA Artificial Sequence Description of Artificial Sequence Synthetic oligonucleotide 27 accaacagcg acaataatca ca 22 28 21 DNA Artificial Sequence Description of Artificial Sequence Primer 28 cagtatgact gaacgcttgg c 21 29 21 DNA Artificial Sequence Description of Artificial Sequence Primer 29 gcgataacat gcccttcttc a 21 

1. A mutant lactic bacteria with a capacity for overexpressing one or more peptidases, wherein gene codY is inactivated.
 2. The mutant lactic bacteria according to claim 1, wherein said inactivation is total or partial.
 3. The mutant lactic bacteria according to claim 1, wherein the DNA sequence of said gene or of a sequence implicated in expression or regulation of said gene is modified.
 4. The mutant lactic bacteria according to claim 1, wherein a gene coding for a cofactor protein required for activity of said gene and/or modification of a gene implicated in expression or regulation of this cofactor protein is modified.
 5. The mutant lactic bacteria according to claim 1, wherein the lactic bacterium is L. lactis.
 6. The mutant lactic bacteria according to claim 1, wherein the lactic bacterium is S. thermophilus.
 7. A recombinant vector for identifying or selecting mutant lactic bacteria according to claim 1, comprising a marker gene fused to a peptidase gene or a promoter of said gene, a replication origin inactivated after integration in the bacteria, an antibiotic marker and at least a part of gene cluA.
 8. A method for identifying or selecting a mutant lactic bacterium according to claim 1, comprising: transferring a peptidase gene or a promoter of said gene into a bacterium by conjugation with a vector comprising a marker gene fused to a peptidase gene or a promoter of said gene, a replication origin inactivated after integration in the bacteria, an antibiotic marker and at least a part of gene cluA; culturing said bacteria in the presence of peptides; and measuring activity of the reporter gene. 